editing in arcmaphturner/ce484/arcediting.pdf · iii 1 introduction 1 rich suite of graphical...

Editing in ArcMap™

Jeff Shaner and Jennifer WrightsellGIS by ESRI ™

Copyright © 2000 ESRIAll rights reserved.Printed in the United States of America.

The information contained in this document is the exclusive property of ESRI. This work is protected under United States copyright law and otherinternational copyright treaties and conventions. No part of this work may be reproduced or transmitted in any form or by any means, electronic ormechanical, including photocopying and recording, or by any information storage or retrieval system, except as expressly permitted in writing by ESRI. Allrequests should be sent to Attention: Contracts Manager, ESRI, 380 New York Street, Redlands, CA 92373-8100, USA.

The information contained in this document is subject to change without notice.

DATA CREDITS

Graphical Editing Map: Wilson, North Carolina

Universal Data Editor Map, Editing in data view and layout view map: Greeley ColoradoContext menus and shortcut keys map: P.F.R.A., Regina Saskatchewan CanadaQuick-Start Tutorial Data: Wilson, North Carolina, Greeley Colorado

CONTRIBUTING WRITERSBill Moreland, Doug Morgenthaler, Jan van Roessel, Jeff Jackson, Kristin Clark, Michelle Sakala, Robin Floyd, Steve Van Esch, Tim Hodson, WayneHewitt

U.S. GOVERNMENT RESTRICTED/LIMITED RIGHTSAny software, documentation, and/or data delivered hereunder is subject to the terms of the License Agreement. In no event shall the U.S. Governmentacquire greater than RESTRICTED/LIMITED RIGHTS. At a minimum, use, duplication, or disclosure by the U.S. Government is subject to restrictionsas set forth in FAR §52.227-14 Alternates I, II, and III (JUN 1987); FAR §52.227-19 (JUN 1987) and/or FAR §12.211/12.212 (Commercial TechnicalData/Computer Software); and DFARS §252.227-7015 (NOV 1995) (Technical Data) and/or DFARS §227.7202 (Computer Software), as applicable.Contractor/Manufacturer is ESRI, 380 New York Street, Redlands, CA 92373-8100, USA.

ESRI, ArcView, and the ESRI globe logo are trademarks of ESRI, registered in the United States and certain other countries; registration is pending inthe European Community. ArcMap, ArcInfo, ArcSDE, ArcEditor, ArcGIS, ArcCatalog, ArcObjects, ARCEDIT, GIS by ESRI, and the ESRI Presslogo are trademarks and www.esri.com is a service mark of ESRI.

Other companies and products mentioned herein are trademarks or registered trademarks of their respective trademark owners.

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iii

1 Introduction 1Rich suite of graphical editing tools 2Universal data editor 3Editing in data view and layout view 4Context menus and shortcut keys for increased productivity 5Multiuser editing with version management and conflict detection 6Editing in projected space 7Tips on learning how to edit in ArcMap 8

2 Quick-start tutorial 11Exercise 1: Creating polygon features 12Exercise 2: Creating line features 17Exercise 3: Using a digitizing tablet 22Exercise 4: Editing features 27Exercise 5: Editing topological features 35Exercise 6: Working with CAD drawings 42

3 Editing basics 49An overview of the editing process 50The Editor toolbar 52Exploring the Editor toolbar 53Adding the Editor toolbar 59Adding the data you want to edit 60Starting and stopping an edit session 61Selecting features 64Moving features 68Deleting features 72Copying and pasting features 73Setting the number of decimal places used for reporting measurements 74

Contents

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iv EDITING IN ARCMAP

124 Creating new features 75

How to create a new feature 76Creating point features and vertices 80Creating lines and polygons 88Creating segments using angles and lengths 94Creating segments using angles from existing segments 98Creating segments that are parametric curves 102Creating segments by tracing features 105The Snapping Environment window 106Types of snapping properties 107Using the snapping environment 108

5 Using a digitizer 111Setting up your digitizing tablet and preparing your paper map 112Registering your paper map 113Creating features using a digitizer 117Digitizing features in point mode 118Digitizing features in stream mode 120

6 Creating features from other features 123Copying a line at a specific interval 124Creating a buffer around a feature 126Creating a mirror image of a feature 128Merging features from the same layer into one feature 130Combining features from different layers into one feature 132Creating a feature from features with common areas 134

7 Editing existing features 137Splitting a line or polygon 138Trimming a line 142Extending a line 145Flipping a line 147

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CONTENTS v

Placing points along a line 148Reshaping a line or polygon 150Adding and deleting sketch vertices 152Moving a vertex in a sketch 154Changing the properties of a sketch 159Scaling features 163Clipping features 165Stretching geometry proportionately 166Stretching a feature�s geometry proportionately 167

8 Editing topological features 169Integrating topological data 170Integrating data 171Moving a shared vertex or boundary 173Reshaping a shared boundary 175Modifying a shared boundary 177Creating a new polygon with shared parts 179

9 Editing attributes 181Viewing attributes 182Adding and modifying attributes 184Copying and pasting attributes 186

Appendix A: Editing coverages in ArcMap 189

Glossary 209

Index 223

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toc.p65 01/10/2001, 9:53 AM6

IN THIS CHAPTER

1

Introduction

• Rich suite of graphical editingtools

• Universal data editor

• Editing in data view and layoutview

• Context menus and shortcut keysfor increased productivity

• Multiuser editing with versionmanagement and conflict detec-tion

• Editing in projected space

• Tips on learning how to edit inArcMap

1In addition to mapmaking and map-based analysis, ESRI®ArcMap� is theapplication for creating and editing geographic data as well as tabular data.With ArcMap, you can edit shapefiles, coverages, and geodatabases all withone common user interface. ArcMap contains sophisticated, CAD-basedediting tools that help you construct features quickly and easily whilemaintaining the spatial integrity of your GIS database.

Whether you use ArcView® GIS or ArcInfo�, you use the same editingtools in ArcMap to work on your geographic data. In cases where yourorganization has multiple users simultaneously editing on a sharedgeodatabase, ArcMap, in concert with ArcSDE�, provides the toolsnecessary to manage long editing transactions, as well as to manage versionsand resolve potential conflicts.

Whether you use ArcView GIS, ArcEditor�, or ArcInfo, the goal of thisbook is to help you learn and use the editing capabilities in ArcMap for anylevel of geographic database maintenance. The next few pages highlightsome of the features you will find invaluable while editing in ArcMap.

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2 EDITING IN ARCMAP

Rich suite of graphical editing toolsArcMap helps you create and edit geographic features quickly and easily by including many of the graphic editing functions popularwith the latest computer-aided design (CAD) editing packages.

Sketch construction tools in ArcMap will allow you to quickly and accurately edit street rights-of-way.

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INTRODUCTION 3

Universal data editorArcMap lets you edit shapefiles, coverages, and geodatabases in their native data formats. Also, you can edit an entire folder of data atonce.

Pick the folder of data that you want to edit when you start editing in ArcMap.

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4 EDITING IN ARCMAP

Editing in data view and layout viewArcMap provides two different ways to view a map: data view and layout view. Each view lets you look at and interact with the map in adifferent way. Data view hides all of the map elements on the layout such as titles, North arrows, and scale bars. In layout view, you�llsee a virtual page upon which you can place and arrange map elements. You can edit your geographic data in either data view or layoutview.

Maximize the display of geographic information whenediting using data view.

When you are preparing a map, you can edit features directly usinglayout view.

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INTRODUCTION 5

Context menus and shortcut keys for increased productivityArcMap contains numerous context menus and shortcut keys to help you create and edit features quickly.

Use the sketch tool context menu and shortcut keys to access advanced feature creation tools.

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6 EDITING IN ARCMAP

Multiuser editing with version management and conflict detectionIf you have several users that need to edit the same data at the same time, ArcMap can help you manage versions of your ArcSDEgeodatabase.

Sophisticated version management tools in ArcMap will help you maintain a multiuser editing environment.

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INTRODUCTION 7

Editing in projected spaceIf you�ve collected data from a variety of sources, chances are that not all layers contain the same coordinate system information. UsingArcMap, you can set the coordinate system for a data frame. As you add layers to your map, they are automatically transformed to thatprojection. That means that you can edit the shapes and attributes of a layer regardless of the coordinate system it was stored in.

ArcMap has “project-on-the-fly” capabilities that let you edit layers in the coordinate system that is mostimportant to you without having to transform your data.

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8 EDITING IN ARCMAP

Tips on learning how to edit in ArcMap

If you�re new to GIS, remember that you don�t have to learneverything about editing in ArcMap to get immediate results.Begin learning how to edit by reading Chapter 2, �Quick-starttutorial�. In Chapter 2, you�ll learn how easy it is to use thevarious editing tools in conjunction with ArcMap, and you�ll gaininsight into the steps you can take to complete certain tasks.ArcMap comes with the data used in the tutorial, so you canfollow along step by step at your computer. You can also read thetutorial without using your computer.

Finding answers to your questions

Like most people, your goal is to complete your tasks whileinvesting a minimum amount of time and effort in learning howto use software. You want intuitive, easy-to-use software thatgives you immediate results, without having to read pages ofdocumentation. However, when you do have a question, you wantthe answer quickly so that you can complete your task. That�swhat this book is all about�getting you the answers you need,when you need them.

This book describes editing tasks�from basic to advanced�thatyou�ll perform with ArcMap. Although you can read this bookfrom start to finish, you�ll likely use it more as a reference. Whenyou want to know how to do a particular task, such as creating anew feature, just look it up in the table of contents or index. Whatyou�ll find is a concise, step-by-step description of how tocomplete the task. Some chapters also include detailedinformation that you can read if you want to learn more about theconcepts behind the tasks. You may also refer to the glossary inthis book if you come across any unfamiliar GIS terms or need torefresh your memory.

About this book

This book is designed to introduce editing in ArcMap and itscapabilities. The topics covered in the various tasks and thetutorial in Chapter 2 assume you are familiar with building a GISdatabase and the fundamentals of GIS. If you have never used aGIS before or feel you need to refresh your knowledge, pleasetake some time to read Getting Started with ArcGIS, which youreceived in your ArcGIS package. It is not necessary to do so tocontinue with this book, but you should use it as a reference ifyou encounter tasks with which you are unfamiliar.

Chapter 3 is an introduction to editing in ArcMap and describesthe basic tasks you need to know before you can start creatingand editing spatial data. It�s easy to create new features inArcMap, and Chapter 4 describes the different ways you cancreate them.

Chapter 5 illustrates how you can connect a digitizing tablet toyour computer and digitize GIS features from paper maps. Whenediting spatial data, often new features are created using theshapes of other features. Chapter 6 shows you how easy it is toperform these tasks in ArcMap.

Chapter 7 shows how to modify the shapes of features thatalready exist in your database. If you need to maintain topologywhen you edit features, Chapter 8 will show you how. Chapter 9will show you how to edit the attributes of a single feature or allof the selected features in a layer.

You will find that the basic patterns of editing geographic dataare the same across different data models when using the editingtools in ArcMap. However, if you are editing coverage featuressome tools may behave differently depending on the type offeature. Appendix A will explain that behavior in detail.

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INTRODUCTION 9

Getting help on your computer

In addition to this book, ArcMap software�s online Help system isa valuable resource for learning how to use the software.

Contacting ESRI

If you need to contact ESRI for technical support, see the productregistration and support card you received with ArcMap or seethe topic �Contacting Technical Support� in the �Getting morehelp� book of the ArcGIS Desktop Help system. You can also visitESRI on the Web at www.esri.com and www.arconline.esri.com formore information about ArcMap.

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IN THIS CHAPTER

11

Quick-start tutorial

• Exercise 1: Creating polygonfeatures

• Exercise 2: Creating line features

• Exercise 3: Using a digitizingtablet

• Exercise 4: Editing features

• Exercise 5: Editing topologicalfeatures

• Exercise 6: Working with CADdrawings

2ArcMap has the tools you need to create and edit your spatial databases. Itis easy to learn and ensures a simple, quick, and natural transition fromviewing geography to editing geography.

The easiest way to learn how to edit in ArcMap is to complete the exercisesin this tutorial.

Exercises 1 and 2 introduce the edit sketch, sketch tools, and edit tasks andshows you how to use them to create new features quickly and easily.

Exercise 3 walks you through the process of converting features on a papermap directly into your database using a digitizing tablet.

Exercise 4 teaches you how to move, rotate, scale, extend, trim, and modifythe vertices of existing features.

Exercise 5 shows you how to create and maintain the shared boundariesbetween features and layers.

Exercise 6 demonstrates how you can integrate layers from computer-aideddesign (CAD) drawings into your database.

Each of these exercises takes between 15 and 20 minutes to complete. Youhave the option of working through the entire tutorial or completing eachexercise one at a time.

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12 EDITING IN ARCMAP

Exercise 1: Creating polygon features

The editing tools in ArcMap make it very easy to createnew features. You use edit tasks, the edit sketch, sketchtools, and snapping to create new features in ArcMap.

In this exercise, you will digitize a new polygon feature intoa shapefile layer that outlines a land use study region. Thestudy area polygon that you create needs to snap to anindex grid layer that subdivides the entire geographic region.You will begin by starting ArcMap and loading a mapdocument that contains the shapefile layer and ageodatabase that contains the index grid for the region.

Starting ArcMap and beginning editing

Before you can complete the tasks in this tutorial, you muststart ArcMap and load the tutorial data.

1. Double-click a shortcut installed on your desktop or usethe Programs list in your Start menu to start ArcMap.

2. Click the Open button on the Standard toolbar. Navigateto the CreatingNewFeatures.mxd map document in theEditor directory where you installed the tutorial data(C:\ArcGIS\ArcTutor is the default location).

3. Click the Editor Toolbar button on the Standard toolbarto add the Editor toolbar to ArcMap.

4. Click the Editor menu and click Start Editing.

If you only have one workspace in your map, you canstart editing the map layers at this point. In this exercise,two workspaces are loaded in the map, so you will needto choose the workspace you want to edit.

5. Click the Editor folder workspace to start editing thestudyarea.shp shapefile. Click OK. You will edit thegeodatabase in the next exercise.

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QUICK-START TUTORIAL 13

Creating a new polygon feature

This exercise focuses on creating a new study area polygonthat encompasses a parcel CAD drawing. The extent of thestudy area is defined by the index grid lines located in anexisting database. The index grid represents logical divisionswithin the data.

To create the new polygon, you must do �heads-up�digitizing against the index grid and snap the vertices ofyour new polygon to the vertices of the grid lines.

Setting the snapping environment

Before you start editing the study area shapefile, you needto set your snapping environment so that each point you addsnaps to the vertices of features in the index grid. For moreinformation about snapping, see �Using the snappingenvironment� in Chapter 4.

1. Click the Editor menu and click Snapping to display theSnapping Environment window.

2. Check the Vertex check box next to the IndexGrid layerto snap the sketch vertices to the vertices of the indexgrid.

With the snapping environment set, you can create anew study area polygon. Make sure you snap each pointto the thick index grid lines shown below.

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Setting the current task

Before you start digitizing a new feature, you must set thecurrent editing task to Create New Feature.

1. Click the Current Task dropdown arrow and clickCreate New Feature.

To create a new feature, you also need a target layer.The target layer determines the type of feature you willcreate and what layer it will be stored in. Since there isonly one shapefile in the folder that you started to edit,the target layer is set to the study area shapefile bydefault.

Using the Sketch tool

To create a new feature using the Create New Featuretask, you must first create an edit sketch. An edit sketch isa shape that you draw by digitizing vertices using the sketchconstruction tools located on the tool palette.

Several tools can add vertices to the sketch. You will usethe Sketch tool to add the study area polygon.

1. Click the tool palette dropdown arrow and click theSketch tool.

2. Click to add the first vertex of the sketch to the lower-left corner of the thick index grid lines. The vertexshould snap in place.

3. Click to add the remaining vertices, snapping eachvertex to a corner in the index grid. Create verticescounterclockwise until you return to the point locateddirectly above the first vertex that you placed.

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Finishing the sketch

1. Press the F2 key or right-click and click Finish Sketch.

This action adds the final sketch segment and createsthe new feature.

Your new study area polygon is now created. If yousnapped each sketch vertex properly, the new polygonshould look like the shaded polygon below.

Adding attributes

The new feature you created does not contain any attributeinformation. Because other polygon features are present inthis shapefile, distinguish your new polygon from the othersby adding descriptive information about it.

You can add descriptive information for a selected featureusing the Attributes dialog box or �property inspector�.

1. Click the Attributes button on the Editor toolbar to add adescription attribute to the new study area polygon.

2. Click the layer field for the selected feature and type�StudyArea� as a description of the feature.1

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Saving your edits

After you have created the new study area polygon, youcan choose to save or discard your edits by stopping theedit session.

1. Click the Editor menu and click Stop Editing.

2. Click Yes to save the new study area polygon into thestudy area shapefile you were editing or No to discardyour edits.

In this exercise you learned how to quickly and accuratelycreate a new polygon feature. You used the Sketch tool todigitize a polygon shape while snapping each vertex to anexisting vertex in another layer.

There are several other ways that you can construct newfeatures in your GIS database. The next exercise will showyou some of the more advanced methods of constructingvertices in the edit sketch.

For more detailed information about editing tasks andcreating polygon features, see Chapter 4, �Creating newfeatures�.

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Exercise 2: Creating line features

In this exercise, you will update the existing road network inyour database with a new road casing line.

In building the line feature, you will learn how to use someof the more advanced construction methods offered withthe Sketch tool context menu.

Editing the geodatabase

Because the road feature class exists inside a differentworkspace than the study area shapefile, you need to startediting the database before you can create the new line.

1. Click the Editor menu and click Start Editing. Select thepersonal geodatabase as the workspace that you want toedit and click OK.

Locating the update area

Spatial bookmarks are named extents that can be saved inmap documents. Creating a bookmark for areas that youvisit frequently will save you time. For information on howto create and manage spatial bookmarks, see Chapter 3,�ArcMap basics�, in Using ArcMap.

You will now zoom to a spatial bookmark created for thisexercise.

1. Click the View menu, point to Bookmarks, then clickUpdate road casings to set the current view to the editarea of this exercise.

When the display refreshes, note that the top line of thisroad casing is missing from the layer. You must updatethe road casing by adding the missing line.

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Setting the snapping environment

The endpoints of the road casing feature need to snap toadjacent casings to ensure that the new feature isconnected to the existing casing features. Snapping to theend of road casing lines will help you do this.

1. Click the Editor menu and click Snapping. Check theEnd option for the RoadCasings layer to set snapping tothe endpoint of casing features.

Digitizing

After setting the snapping environment, make sure that thetarget layer is set to the RoadCasings layer, and then youcan start digitizing.


2. Move the pointer to the broken section of the roadcasing in the top-left corner of the canvas. Once thepointer is inside the snapping tolerance, the snappinglocation (blue dot) will move away from the pointer.Click the left mouse button to add the first vertex.

Beginning construction

With the first vertex of the new road casing properlyplaced, you can construct the casing line feature. Your newfeature will be connected to that casing.

Setting length and angle measurements

Before creating the second vertex, you must first set thelength of the line.

1. Right-click the map and click Length.

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2. Type a value of 15 map units and press Enter.

If you move the pointer now, notice that you can�t stretchthe line further than your length measurement. This is calleda constraint. To learn more about sketch constraints, seeChapter 4, �Creating new features�.

You must also set an angle constraint to create the secondvertex.

3. Press Ctrl + A and type a value of 260 degrees. PressEnter.

Creating a curve tangent to the last segment

Next, add a curve that is tangent to the last segment youjust added to the sketch. The curve will form the corner ofthe road casing.

1. Right-click and click Tangent curve to enter the curveinformation required to place the next vertex.

2. Click the first dropdown arrow and click Chord. Type�20� to set the chord length. Click the second dropdownarrow and click Delta Angle. Type �90� in the secondtext box for the angle measurement. Click Left toindicate that the new curve will be tangent to the left ofthe previous segment. Press Enter to create the curve.

Creating a vertex relative to the last vertex

Often, construction points are calculated relative to the lastpoint recorded. Using the Delta X, Y sketch constructor,you can add relative vertices.

1. Press Ctrl + D. Type �88� for the x-value and �-9� forthe y-value. Press Enter to add the point.

Creating a vertex parallel to an existing line

You can define the angle measurement for points added tothe sketch in several ways. You can set an absolute valuelike you did in the first step of this exercise, or you can usethe angles of existing features. Quite often, road casingsare constructed using the angles of road centerlines. Sincewe already have one road casing, we can use its angle inconstructing the next segment.

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Creating a tangent curve

One final tangent curve needs to be added to the sketchbefore you can connect it to the existing casing and add thefeature.

1. Press Ctrl + T. Type a chord length of 12 and a deltaangle of 120, then press Enter to create the final curvesegment.

Finishing the sketch

To finish the sketch and create the feature so that it isconnected to the existing casing, you need to snap the lastpoint of the sketch to the endpoint of the existing roadcasing.

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1. Right-click on the lower road casing line. Click Parallel.Press Ctrl + L, type a value of 415, then press Enter.

Creating a new vertex using absolute coordinates

Quite often exact x- and y-coordinate information isavailable for the construction of vertices. Add the nextvertex by typing exact coordinates using the Absolute X, Yconstructor.

1. Right-click on map and click Absolte X, Y. Type�1227820.6� in the x field, press the Tab key, and type�181460.6� in the y field. Press Enter to add the point.

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1. Move the pointer to the endpoint of the existing roadcasing until it snaps. Double-click to add the last point andcreate the feature.

With construction now complete, you can continue tosearch the layer to find additional broken lines and connectthem together, experimenting with these and other sketchtools and construction techniques.

The next exercise will show you how you can use theconstruction methods demonstrated in this exercise tocapture features from a paper map directly into your GISlayers using a digitizing tablet.

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The first step in the first exercise showed you how to�heads-up� digitize features by snapping to an existingvector source. However, often that source information is inpaper form. ArcMap lets you trace over the features youare interested in capturing using a digitizing tablet connectedto your computer. By digitizing data using a tablet, you canget features from almost any paper map into your GISdatabase.

Setting up your digitizing tablet

Before you can start digitizing, you must set up your tabletand prepare the map from which you want to digitize.

Before you can continue with this exercise, you must haveproperly installed the WinTab driver for your tablet andconfigured the buttons on your digitizing puck. If youinstalled the WinTab driver after installing ArcInfo, you willneed to register the digitizer.dll in order to continue. Formore information on digitizers, see Chapter 5, �Using adigitizer�.

Preparing the map

You will now print the paper map from which you want todigitize and attach it to your tablet.

1. Print the �DigitizingFeatures.tif� image located in theEditor tutorial directory (where you installed the tutorialdata) and tape it to your tablet using masking tape.

2. Start ArcMap if you haven�t already done so. Open theDigitizingFeatures.mxd map document to register thepaper map to your map document.

Registering your map for the first time

You must always register your paper map before you canbegin digitizing from it. This involves establishing controlpoints to register the paper map to the geographic space ofyour GIS data.

You can add control points as x,y coordinates stored in acomma-delimited American Standard Code for InformationInterchange (ASCII) file and load those points into yourmap document when you are ready to digitize. However,for this exercise, you will establish these coordinatesmanually as you register the points to known mapcoordinates located on the paper map you printed out.

1. Click the Editor menu and click Start Editing. Click theEditor menu and click Options.

Exercise 3: Using a digitizing tablet

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2. Click the Digitizer tab. You will create and store controlpoints here.

The control points you add will be saved with the mapdocument.

3. Starting with the upper-left corner of your paper mapand working clockwise, locate the point marked �1� andclick on it using the digitizer puck. Then type theassociated ground x,y coordinates indicated on the papermap into the dialog next to the point entered.

4. Digitize and type values for the other three points, thenexamine the total root mean square (RMS) errorcalculation for all points. Error values are displayed inmap and digitizer units. To maintain highly accurate data,the RMS error should be less than 0.004 digitizer units.

To reduce the total RMS error, you can replace points byclicking on the point you want to replace in the EditingOptions menu, then clicking on the paper map to capturea new point. By reentering points with a higherror value, you can reduce the total error.

5. Click Apply to accept the registration after you havereached an acceptable RMS error.

Digitizing modes

You need to enable digitizing mode once you haveregistered your map. Enabling digitizing mode maps thelocation of the puck on the tablet to a specific location onthe screen.

1. Click the Enabled check box on the Digitizer tab of theEditing Options dialog box to enable digitizing mode.

2. Click OK.

Digitizing new features

You are now ready to begin digitizing new features. Youwill add new lot lines representing a new parcel subdivisioninto an existing shapefile of lot lines.

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Setting the current task and target layer

Creating new features using a digitizer puck is identical tocreating new features using the mouse. You must set thecurrent task and target layer before you start digitizing.

1. Click the Current Task dropdown arrow and click CreateNew Feature.

2. Click the Target layer dropdown arrow and click Lotlinesto set the target layer.

Creating new features

There are two ways to digitize features on a paper map:point mode digitizing and stream mode digitizing(streaming). You can easily toggle back and forth betweenpoint and stream mode by pressing F8.

Digitizing in point mode

Point mode is the default and most common method ofdigitizing paper features. To digitize features in point mode,you click to add each point or vertex. If the paper featurewas drafted with considerable accuracy, you should usepoint mode digitizing and snapping to retain that accuracy.

1. Click the Editor menu and click Snapping. Check theEdge option for the Lotlines layer to make sure thefeatures you digitize snap to existing edges.

2. Trace over the frontage lot lines (lines in red) that definethe road leading into the new subdivision. For straightsegments, you should add a vertex where lot linesintersect. Click the Sketch tool and then click on thepaper map to start adding vertices.

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Digitizing in stream mode

When tracing line or polygon features, you may want to addvertices as you move the mouse rather than click each timeyou want to add a vertex. Stream mode digitizing lets youdo this.

Before starting to digitize in stream mode, you need to set astream tolerance�the interval at which the sketch addsvertices along the feature you are digitizing. The defaulttolerance value is 0 map units, so if you don�t enter atolerance value you may find vertices that join or overlapeach other. You will also set the group tolerance for streammode to the same value; this will let you remove numerouspoints in a single undo operation.

1. Click the Editor menu and click Options. Click theGeneral tab and type a new stream tolerance value of45 map units; make sure that the group tolerance is setto 45 as well. Click OK when you are finished settingthe tolerance values.

2. Snap the first point to the exterior of the new lot lines(upper-left corner), then press F8 to start digitizing instream mode. Trace along the boundary of the lots (linesin red) until you reach the last lot (upper-right). Noticethat vertices are added at consistent intervals�45 mapunits apart. Press F8 to stop digitizing in stream mode,snap the last vertex to the existing lot line, and double-click to finish the sketch.

3. With the exterior lot lines digitized, proceed to digitizeeach remaining paper line feature required to define thelots.

Once you are finished digitizing, you should disable thedigitizer puck.

4. Click the Editor menu and click Options. Click theDigitizer tab and uncheck Enabled to disable thedigitizer. Click OK.1

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Finishing your digitizing session

Once you have finished tracing lot lines and have disabledthe digitizer puck, you can stop editing and complete theexercise by saving your edits.


2. Click Yes to save your edits.

In this exercise you learned how to create new featuresand append your GIS database by digitizing shapes directlyfrom a digitizing tablet. The next exercise will show youhow to copy shapes from existing vector sources (CADdrawing layers) and paste them into your GIS database.

To learn more about digitizing, see Chapter 5, �Using adigitizer�. If you need to find out if ArcMap supports yourdigitizing tablet, please consult the ESRI Web site(www.esri.com) for the most recent information.

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Exercise 4: Editing features

In the first three exercises, you learned how to create newfeatures in ArcMap. In this exercise, you�ll learn how tocopy and paste, move, rotate, scale, and extend existingfeatures.

Opening the exercise document and startingediting

1. Start ArcMap.

2. Click the Open button on the Standard toolbar. Navigateto the EditingFeatures.mxd map document located in theEditor directory where you installed the tutorial data(C:\ArcGIS\ArcTutor is the default location).


Copying and pasting features

When creating vector features of the same type as existingones, it is more efficient to copy their shapes than to digitizeover the top of them. You can copy the shapes of anyvector feature that you can select in ArcMap. In this step,you will select buildings from a CAD drawing and pastethem into a geodatabase layer of buildings.

1. Click the Edit tool on the Editor toolbar and drag a boxaround all of the new building features to select them.

All selected CAD features should be highlighted asshown below.

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2. Click the Copy button on the Standard toolbar to copythe selected features to the clipboard.

3. Set the Buildings layer as the target layer so that youcan paste the copied features into it.

4. Click Paste to copy the selected building features intothe target layer. The progress bar will update as eachfeature is copied into the target layer.

It is important to note that only the shapes are copiedfrom the CAD file into the geodatabase. If you need topaste the attributes as well, you must use the objectloader. Exercise 6 of this tutorial shows you how to dothis.

Rotating features

Now that you�ve copied the building features into theBuildings layer of your geodatabase, you need to orient thefeatures to fit the parcel subdivision into which you�ll movethem.

1. To avoid selecting features from the CAD layer (calledNew Buildings), uncheck it in the table of contents tohide its features.

2. Click the Rotate tool on the Editor toolbar.

3. Press the A key, type �180�, and press Enter to rotatethe selected building features 180 degrees.

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The selected features are now oriented 180 degrees fromtheir previous location.

Moving features

Now that the buildings are oriented properly, you are readyto move and scale them so that they fit inside thesubdivision located near the bottom center of the map.

You can ensure the proper relocation of the buildingfeatures by snapping the lower-left selected building featureto the endpoint of the lower-left water service line (shownin red).

1. With the buildings selected, click the Editor menu andclick Snapping.

2. Check the End option for the Water layer and the Vertexoption for the Buildings layer so that you can snap thecorner of a building feature to the endpoint of awaterline.

3. Click the Edit tool so that you can move the selectionanchor for selected features.

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The selection anchor is a small x located at the center ofselected features. It is the point on the feature or groupof features that will be snapped when you move them.

4. Hold the Ctrl key down and move the pointer over theselection anchor. When the pointer icon changes, clickand drag the selection anchor until it snaps to the cornerof the lower-left building.

5. Drag the selected buildings until they snap to theendpoint of the waterline.

Notice that some of the buildings are too large to fit insidethe parcels. You must scale these features to make themfit.

Scaling features

When data is created using a coordinate system differentfrom that of your database, you may need to adjust theprojection and scale of the data to fit the projection andscale of your database. Often, simply moving, rotating, andscaling those features are sufficient.

Because scaling is not a common operation, the Scale toolis not located on the Editor toolbar. You must therefore addit to the toolbar before you can use it.

1. Click the Tools menu and click Customize.

2. Click the Commands tab and click Editor in theCategories list. The Editor category contains all editingtools, regardless of their location.

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3. Scroll down the list of commands on the right until youfind the Scale tool. Drag and drop the tool next to theRotate tool on the Editor toolbar. Click Close on theCustomize dialog box.

4. Before scaling the selected features, you may want tozoom in so that your scaling is more accurate. Click theSelection menu and click Zoom To Selected Features.

5. Click the Scale tool and drag the selected buildingfeatures to scale them. Shrink the features until they fitinside the parcel subdivision. Use the waterlines as aguide. Scale features until the lower-right buildingmatches the endpoint of the waterline.

Extending and trimming waterlines using theExtend/Trim features task

Now that you have scaled the building features to fit insidethe parcel subdivision, you need to extend the waterlines sothat they snap to the side of each building. You can extendand trim waterlines using the Extend/Trim Features task.

1. To get a better view of the waterline that you need toextend, you can zoom in to the Extend Water Linebookmark. Click the View menu, click Bookmarks, andclick Extend Water Lines.

2. Click the Current Task dropdown arrow and clickExtend/Trim Features to set the edit task.

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3. The Extend/Trim edit task will extend selected polylinefeatures to the sketch you digitize. Click the Edit tooland click the waterline feature that you need to extend.

4. Click the Sketch tool and snap the first sketch point tothe upper-right corner of the building feature you wantto extend to.

5. Move the pointer until it snaps to the upper-left buildingcorner and double-click to finish the sketch. Thewaterline will then extend until it intersects the line thatyou have digitized. Since the line is identical to the sideof the building, the end of the waterline should snap tothe building.

You can also use the Extend/Trim features task to cut awaterline feature if it extends too far into the building.

6. To get a better view of the waterlines, you must zoom tothe bookmarked extent called Trim Water Line, whichwas created for you. Click the View menu, point toBookmarks, and click Trim Water Line.

7. Click the Edit tool and click to select the waterline thatextends into the building and needs to be trimmed.

8. If you changed the current task, make sure that youchange it back to Extend/Trim Features, then click theSketch tool to start digitizing.

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9. Snap the first sketch point to the lower-left corner of thebuilding feature.

10. Move the pointer to the upper-left corner of the building.Double-click to snap the last point of thesketch to the building corner and trim the waterlinefeature.

Extending and trimming waterlines using theModify Features task

The Extend/Trim features task lets you extend and trimselected waterlines using a sketch that the features eithercross or extend to. However, that is not the only method forextending or trimming waterlines. You can move, insert, orremove vertices of the waterline by making its shape theedit sketch. You can do this using the Modify Features task.

1. To get a better view of the waterlines, you need to zoomto the bookmarked extent called Modify Water Line.Click the View menu, point to Bookmarks, and clickModify Water Line.

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2. Click the Edit tool and click to select the waterlinefeature that needs to be extended.

3. Click the Current Task dropdown arrow and clickModify Feature to display the vertices of the waterline.

4. Click the Edit tool and move the pointer over the redvertex at the end of the waterline. Drag the vertex untilit snaps to the building corner.

5. Move the pointer over the red vertex, right-click, thenclick Finish Sketch to finish modifying the waterline.

You can follow the same steps to trim line features usingthe Modify Features task. You can use the Trim commandto reduce the length of the sketch by an exact distance aswell.

With modifications to these waterlines completed, continuemodifying the rest of the waterlines that don�t connect tobuilding features and experiment with other methods ofmodifying shapes.

For more information about editing features, see Chapter 7,�Editing existing features�.

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Exercise 5: Editing topological features

Most vector datasets have features that share commonboundaries or points. Features that share commonboundaries or points are said to have a topologicalassociation.

ArcMap lets you create and maintain topologicalassociations between features and feature classes whenyou edit shapefiles, coverages, or feature datasets.

In the previous exercise, you learned how to create andmanipulate individual features. In this exercise, you�ll learnhow to create and maintain topological associationsbetween features.

Opening the exercise document

1. Start ArcMap.

2. Click the Open button on the Standard toolbar. Navigateto the EditingTopoFeatures.mxd map document locatedin the Editor directory where you installed the tutorialdata (C:\ArcGIS\ArcTutor is the default location).

Integrating topological data

The dataset for this exercise contains state and countypolygon layers for Ohio and West Virginia, as well as anOhio River line layer.

The state, county, and river layers were taken fromdifferent data sources; they don�t share commonboundaries with each other. In order to update theboundaries that are shared between these features, youmust create topological associations.

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You�ll begin by integrating all of the layers together so thatall features with parts that should be shared are shared.


The Integrate command lets you create topologicalassociations between features. It makes all boundariesor vertices within a certain distance range identical orcoincident. This distance range is called the clustertolerance. You can choose to integrate only what yousee or the entire dataset.

For this exercise, you must set the cluster tolerance to avalue of 0.001 map units and integrate the entire datasetat that tolerance value.

2. Click the Editor menu and click Options. Click theTopology tab.

3. Uncheck the option to Integrate the visible extent only sothat you can integrate the entire dataset.

4. Type �0.001� for the cluster tolerance value and clickOK.

5. Click the Editor menu and click Integrate. This createstopological associations for the entire dataset.

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Once you click Integrate, a progress indicator willappear. When the Integrate process is complete, you cananalyze the result by zooming to the bookmarked extentcalled Integrate Result.

6. Click the View menu, point to Bookmarks, and clickIntegrate Result.

You can see your results by clicking the Undo button andthen the Redo button at this zoomed extent. You shouldnotice that the county and state boundaries are identical tothe river that passes through them.

Reshaping a shared boundary

Now that the dataset has been integrated, you can start tomodify the shared boundaries between features.

1. Click the View menu, point to Bookmarks, and clickUpdate Meander.

When the display updates, you should see a discrepancybetween the boundary of the states and counties and theriver layer. The meander, or bend, in the river layer isnot accounted for in the state and county layers.

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You can update the state and county layers so that theymatch the same boundary as the river feature by justreshaping the shared boundary between all of the stateand county features. You can do this using the SharedEdit tool.

2. Click the Shared Edit tool.

3. Click the shared boundary you want to update.

When you select a boundary with the Shared Edit tool,all the features in all the layers in the dataset that sharethis boundary are selected. This way, when you movepart of a feature that is shared, any coincident andconnected vertices underneath will move appropriately.This is true even for layers that aren�t visible on themap.

With the shared boundary selected, you can update thestate and county features to match the river line by usingthe Reshape Feature edit task.

4. Click the Current Task dropdown arrow and clickReshape Feature.


6. Right-click over the river line and click Replace Sketch.

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7. Right-click and click Finish Sketch or press F2.

Both the Washington County and Wood County polygonfeatures, as well as Ohio and West Virginia state polygonfeatures, should now share the same meandering part of theriver.

Modifying a shared boundary

Sometimes, updating a shared boundary is as simple asmoving a couple of vertices. You can do this using theModify Features task.

1. Click the View menu, point to Bookmarks, and clickUpdate Meander 2.

2. Click the Shared Edit tool on the Editor toolbar, choosethe shared state/county boundary, and double-click toupdate it.

Before you move any vertices of the shared boundary,set the snapping environment so that each vertex of theshared boundary snaps to the river line.

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6. Right-click between the second and third vertex andclick Insert Vertex.

7. Click and drag the new vertex until it snaps to thebottom-left vertex of the river line.

8. Move the second-to-last vertex until it snaps to the riverline vertex located at the bottom left.

9. Right-click and click Finish Sketch or press F2 to finishediting the shared edge and update all features.

3. Click the Editor menu and click Snapping.

4. Check the Vertex option for the OhioRivers layer.

5. Click the Edit tool and drag the pointer over the secondvertex until it snaps to the river line.

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In this exercise, you used the topology tools in ArcMap tocreate topological associations between layers thatrepresented the same geographic feature but had slightlydifferent shapes. This is important when performing spatialanalysis on layers that you attain from different sources.

With each task, you made sure that topological associationswere maintained by only updating the shared boundariesbetween features.

For a more detailed discussion of the topics mentioned inthis exercise, see Chapter 8, �Editing topological features�.

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Exercise 6: Working with CAD drawings

ArcMap lets you seamlessly integrate computer-aideddesign (CAD) drawings into your work. It allows you todisplay and query CAD datasets without first having toconvert the drawing files to an ESRI format.

The ability to work with CAD drawings in ArcMap isparticularly useful if your organization has existing CADdata resources that you need to use immediately in yourwork.

Not only can you perform basic query and analysisfunctions using ArcMap tools, but you can also snap directlyto CAD features or entities when you update yourdatabase.

This exercise will show you how to import CAD featuresdirectly into your edit session; this will allow you to easilyintegrate CAD features into your work.

Opening the Exercise document

1. Start ArcMap.

2. Click the Open button on the Standard toolbar. Navigateto the WorkingWithCAD.mxd map document located inthe Editor directory where you installed the tutorial data(C:\ArcGIS\ArcTutor is the default location).

3. Zoom to the area of the map identified by the red hashedpolygon.

Using the Load Objects Wizard

You can import CAD entities directly from CAD featureclasses using the Load Objects Wizard. However, you�llneed to add the Load Objects Wizard into ArcMap first.

1. Click the Tools menu and click Customize. Click theCommands tab.

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2. Click the Data Converters category from the Categorieslist and drag and drop the Load Objects command ontothe Editor menu. Close the Customize dialog box.

3. Select the Editor menu and click Start Editing. Set thetarget layer to the LotLines layer. This is the layer intowhich you will load the parcel lines.

Loading CAD features

With the target layer set to the lot lines feature class, youare ready to load features directly from the CAD drawing.

CAD drawings are represented in two ways: CAD drawingfiles and CAD drawing datasets. CAD drawing datasetscontain feature classes organized by point, line, or polygonshape types.

Each CAD feature in a CAD feature class contains aLayer field; it lets you identify the CAD drawing layer thateach feature is derived from. In this exercise, you�ll extractthe features belonging to the lot line layer of the polylinefeature class into your empty lot line geodatabase featureclass.

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1. Click the Editor menu and click Load Objects wizard.

2. Click the Browse button (located to the right of the Inputdata list). Navigate to where you installed the ArcTutorsample data (C:\Esri\ArcTutor by default), then navigateto the Editor\ExerciseData\EditingCAD directory.

3. Double-click the Parcels.dwg drawing dataset. Choosethe Polyline feature class and click the Open button.

4. Click the Add button to add the CAD feature class(listed in the Input data list) to the list of source data toload.

5. Click Next.

Matching input and target fields

The next step in the wizard lets you match the fields of theCAD feature class with the fields in your target layer.

1. Accept the default field mappings for this exercise. ClickNext.

Defining a query

Since all CAD layers are combined into a single featureclass containing a Layer attribute value, you will define anattribute query so that only features with a layer name =�LOT-L� will be loaded into the target layer.

1. Click the option to load only features that satisfy thequery.

2. Click Query Builder to define the query.

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3. Double-click Layer in the Fields list. This adds the stringto the where clause for the query.

4. Click the equals (=) sign.

5. Click Complete List to display all unique attribute valuesfor the Layer field. Double-click LOT-L from the list tocomplete the query.

After completing the steps above, your query shouldread: "Layer" = 'LOT-L'. You can alter the query bytyping directly into the SQL query dialog box.

6. Click Verify to ensure that you have created a valid SQLwhere clause.

7. Click OK. Make sure that you have a valid queryexpression before applying the query to the wizard.

Snapping and validation

Next, the Object Loader will ask you if you want to applyany snapping agents that you have set in the SnappingEnvironment window to features as they are loaded into themap, and/or whether you want to validate each feature thatis added.

If you�re concerned about the connectivity betweenfeatures that you import and existing features in yourdatabase, you may want to apply snapping. However, youshould be aware that features will move within the currentsnapping tolerance. If the source CAD data wasconstructed using coordinate geometry, applying snappingmay reduce the accuracy of the original data.

1. Click Next (do not apply snapping).

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Completing the wizard and loading features

The final dialog box provides a summary of the options thatyou chose through each step of the wizard. You canexamine each of your steps and click Back if you made anymistakes.

1. Click Finish.

A progress indicator will appear.

Once the wizard has finished loading features, you mayneed to refresh the display to see the new lot lines.

Saving your edits

Now that you have successfully loaded CAD data into youredit session, you can stop editing and save your edits.


2. Click Yes to save your edits.

In this exercise, you learned how to load CAD featuresdirectly into your GIS database. You were able to importfeatures by their shape type and by their CAD layer nameusing the Load Objects wizard. But you don�t have toimport CAD data to use it. You can also snap directly toCAD features or simply display and query their attributes.For more information about CAD drawings, see UsingArcCatalog.

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In the first two exercises, you learned how to use the editsketch and sketch tools to create new features. There are alot of additional methods for creating features that were nottouched upon in these exercises. To learn about more waysto create new features, see Chapter 4, �Creating newfeatures�.

In addition to digitizing new features using the mouse, youlearned how to use a digitizer puck and tablet to capturedata from paper maps. Exercise 3 showed you how you canattach a paper map to your digitizing tablet, register thepaper map to the coordinate space of your GIS database,and add features using the puck. To learn more about usinga digitizing tablet, see Chapter 5, �Using a digitizer�.

In exercise 4, you learned how easy it is to modify theshape of existing features. You copied and pasted buildingsfrom a CAD file into your GIS database; you also moved,rotated, and scaled the buildings to match a parcelsubdivision using some of the editing tools in ArcMap. Oncethe buildings were properly placed, you used the Extend/Trim and Modify Feature edit tasks to connect waterservice lines to the side of each building. To learn moreabout editing features in ArcMap, see Chapter 7, �Editingexisting features�.

You can edit multiple features at the same time in ArcMapand ensure that the boundaries between them areconsistent. In Exercise 5, you learned how to use theIntegrate command to create common boundaries betweenstate, county, and river features that were compiled fromdifferent sources at different levels of accuracy. You thenupdated both the state and county boundaries to match thechanges (meanders) in the river features using the SharedEdit tool.

In the last exercise, you learned how to update your existingdata with features in a CAD drawing file using the LoadObjects wizard. You defined a query based on the lot lineCAD layer type and then loaded only those features intoyour target layer.

Whether importing CAD data, using a digitizer to capturefeatures from paper, or editing the shared boundariesbetween polygon features, ArcMap provides the tools youneed to edit your data quickly and easily.

The next chapter will provide an overview of editing inArcMap. It will show you where to find the tools that youneed to use and describe the basic tasks you need to knowbefore you start editing in ArcMap.

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ch2.p65 01/10/2001, 10:23 AM48

IN THIS CHAPTER

49

Editing basics

• An overview of the editing pro-cess

• Exploring the Editor toolbar

• Adding the Editor toolbar

• Adding the data you want to edit

• Starting and stopping an editsession

• Selecting features

• Moving features

• Deleting features

• Copying and pasting features

• Setting the number of decimalplaces used for reportingmeasurements

3In addition to mapmaking and map analysis, ArcMap is also the applicationfor creating and editing your spatial databases. ArcMap has tools to editshapefiles, coverages, and feature datasets�any type of vector data in yourGIS database.

This chapter provides an introduction on how to edit in ArcMap anddescribes the basic tasks you need to know before you can start to createand edit spatial data. For instance, this chapter shows you how to performsuch tasks as adding the Editor toolbar, starting and stopping an edit session,and selecting features.

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An overview of the editing process

The following is a general overview of how to use ArcMap andthe Editor toolbar to edit your data. Each of the following steps isoutlined in detail in this chapter or other chapters in this section.

1. Start ArcMap.

2. Create a new map or open an existing one.

3. Add the data you want to edit to your map.

If there are no existing layers for the feature classes you wantto edit, you can create them using ArcCatalog�. For moreinformation on creating a feature layer, see Using ArcCatalog.

4. Add the Editor toolbar to ArcMap.

New map file button

Open button

Add data button

Editor Toolbar button

5. Choose Start Editing from the Editor menu.

6. Create or modify features and/or their attributes.

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EDITING BASICS 51

7. Choose Stop Editing from the Editor menu and click Yeswhen prompted to save your edits.

There is no need to save the map�all edits made to thedatabase will automatically be reflected the next time youopen the map.

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The Editor toolbar

Edit sessioncommands.

Edit tool:Lets you selectfeatures andmodify them.

Tool palette:Use these toolsto create asketch.

Current Taskdropdown list:The tasks in this listwork with a sketchdrawn with thesketch constructiontools on the toolpalette.

Target layerdropdown list:Sets the layer towhich newfeatures willbelong.

Attributes button:Opens the

attributes dialogbox, which shows

attributesfor all selected

features.

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EDITING BASICS 53

This section shows you how editing in ArcMap helps youcomplete the tasks that you need to do. You�ll learn about thetypes of data you can edit as well as the basics of creating andmodifying features and their attributes.

The structure of vector datasets

ArcMap provides a common editing environment for featuresstored in all types of geographic datasets: feature datasets,coverages, and shapefiles.

When you edit data with ArcMap, you edit feature classes(collections of features) that the layers on your map represent.

Comparing the structure of vector datasets

Geodatabase Coverage Shapefile

Collections A geodatabase is a collection An ArcInfo workspace is a collection A shapefile folder is a collectionof datasets of feature datasets. of coverages. of shapefiles.

Datasets A feature dataset is a collection A coverage is a collection of coverage A shapefile has one shapefile featureof feature classes. feature classes. class.

Collections A feature class is a collection A coverage feature class is a collection A shapefile feature class is aof features of features of the same type. of coverage features. collection of shapefile features.

Features Point, multipoint, polyline, Primary coverage feature classes: Point, multipoint, line, andpolygon, annotation, and point or label point, arc, and node. polygon.network. Secondary feature classes: polygon, tic,

link, section, and annotation.Compound feature classes: regionand route.

Exploring the Editor toolbar

Editing the feature classes lets you edit the actual data source, notjust the representation on the map.

A feature class is a collection of the same type of features, forexample, a collection of points or a collection of polygons. Foreach type of geographic dataset, the available types of featuresvary (see table below).

A dataset is a collection of feature classes that share the samespatial reference. A dataset might be a collection of land basefeature classes or a collection of utility feature classes. Shapefilesare an exception; they do not hold a collection of feature classes,but only one shapefile feature class.

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Building as sketch Building as feature

A collection of feature datasets is stored in a geodatabase.Coverages are stored in an ArcInfo workspace, and shapefiles arestored in a shapefile folder. Although you may add multiplecollections of datasets to your map (geodatabases, ArcInfoworkspaces, and shapefile folders), you can only edit featureclasses within one collection at a time. Also, some coveragefeature classes can�t be edited�link, section, annotation, andgroup feature classes.

What is a sketch and how does it work with atask?

A sketch is a shape you draw that performs various tasks whenediting such as adding new features, modifying features, andreshaping features. Tasks are listed in the Current Task dropdownlist. You must create a sketch in order to complete a task.

For instance, the Create New Feature task uses a sketch youcreate to make the new feature.

Current Task dropdown list

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EDITING BASICS 55

Sketch showing where the polygon is to be “cut”.

Polygon divided into two features where the sketch was drawn.

Parcels intersected by the sketch are now selected.

Sketch intersects parcels to be selected.

The Select Features Using a Line task uses a sketch you create toselect features; the features the line intersects are selected.

The Cut Polygon Features task uses a line sketch you draw to cuta polygon.

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point feature

line feature

polygon feature

line sketch

polygon sketch

Creating new features

You can create three main types of features with the Editortoolbar: points, lines, and polygons.

To create a line or polygon, you must first create a sketch. Asketch�s shape is composed of all the vertices and segments of thefeature. Vertices are the points at which the sketch changesdirection, such as corners, and segments are the lines that connectthe vertices.

You can create a sketch by creating the vertices and segments thatmake up the features. Vertices are marked in green, with the lastvertex added marked in red.

The Sketch tool is the tool you use most often to create a sketch.It has an accompanying context menu that helps you placevertices and segments more accurately. The Arc tool, theDistance�Distance tool, and the Intersection tool (located withthe Sketch tool on the tool palette) also help you create verticesand segments using other construction methods.

Sketch tool context menu

Sketch tool

Arc tool

Intersectiontool

Distance–Distance tool Tool

paletteTrace tool

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EDITING BASICS 57

When you�re creating a new feature, the target layer determinesin which layer a new feature will belong. The Target layerdropdown list contains the names of all the layers in the datasetswith which you�re working. Subtypes are also listed, ifapplicable. For instance, if you set the target layer to �Buildings:Commercial�, any features you create will be part of the�Commercial� subtype of the �Buildings� layer.

You must set the target layer whenever you�re creating newfeatures�whether you�re creating them with the Sketch tool, bycopying and pasting, or by buffering another feature.

Modifying features

For every feature on the map, there is an alternate form, a sketch.In the same way that you must create a sketch to create a feature,to modify a feature you must modify its sketch. Because thevertices are visible in a sketch, you can edit the feature in detail;you can move the vertices, delete them, or add new ones usingthe Sketch context menu.

Besides editing a feature by working with its sketch, you can alsouse another sketch you create to modify the feature for certaintasks. An example of this type of task is Cut Polygon Features,where a sketch you construct is used to divide one polygon intotwo.

Simple modifications to features, such as moving, copying, ordeleting, can be made by selecting the feature and choosing theappropriate tool or command.

Target layer dropdown list

When you edit a feature’s sketch, you edit its vertices using the Sketchcontext menu.

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Editing attributes

Attributes can be created or edited in the Attributes dialog box.After selecting the features whose attributes you want to edit,click the Attributes button to see the dialog box.

Attributes dialog box

Attributes button

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EDITING BASICS 59

Adding the EditortoolbarBefore editing geographicfeature data within ArcMap,you must first add the Editortoolbar.

1. Start ArcMap.

2. Click the Editor Toolbarbutton on the ArcMapStandard toolbar to displaythe Editor toolbar.

3. Click the toolbar’s title barand drag it to the top of theArcMap application window.

Tip

Adding the Editor toolbarusing the Customize dialogboxClick the Tools menu and clickCustomize. Click the Toolbars taband check Editor.

Tip

Adding the Editor toolbarfrom the View menuYou can also add the Editortoolbar by clicking the View menu,pointing to Toolbars, and checkingEditor.

Tip

Adding the Editor toolbarfrom the Tools menuYou can also add the Editortoolbar from the Tools menu. ClickTools and click Editor Toolbar.

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Adding the datayou want to editBefore you can start editing,you must add the data youwant to edit to your map. InArcMap, you can edit datasetsin shapefile, coverage, orgeodatabase format.

1. Start ArcMap.

2. Click the Add Data button.

3. Navigate to the location ofyour data and click Add.

The data is added to yourmap.

2

Tip

Stopping the drawing ofdataYou can stop the drawing processwithout clearing the map bypressing the Esc key.

3

Data is added to the map.

Tip

Loading data from ageodatabaseYou can import features from ageodatabase into a layer on yourmap using the Load Objectscommand. For more information,see Building a Geodatabase.

ch3.p65 01/10/2001, 10:38 AM60

EDITING BASICS 61

Starting an edit session

1. Start ArcMap and add theEditor toolbar.

2. Click Editor and click StartEditing.

The Editor toolbar is nowactive.

Starting andstopping an editsessionAll editing takes place within anedit session. To begin, chooseStart Editing from the Editormenu. The edits you make areimmediately visible on your mapbut are not saved to the databaseuntil you choose to do so.

If you�re working with largeamounts of data, you can speedup the editing and selection offeatures by creating an editcache. An edit cache holds thefeatures visible in the currentmap extent in memory on yourlocal machine. An edit cacheresults in faster editing becauseArcMap doesn�t have to retrievedata from the server. You cancreate an edit cache by clickingthe Build Edit Cache commandon the Edit Cache toolbar. u

Tip

Editing a map with morethan one collection ofdatasetsYou can only edit one collection ofdatasets�one workspace�at atime. These can be geodatabases,ArcInfo coverages, and shapefiles.If your map contains more thanone collection, when you chooseStart Editing you will be promptedto choose which one you want toedit.

2

The Editor toolbar is now active.

ch3.p65 01/25/2001, 7:28 AM61


When you�re finished editing,you can save any changes you�vemade or quit editing withoutsaving. You can also save theedits you�ve made at any time bychoosing Save Edits from theEditor menu.

Tip

Zooming to your edit cacheextentYou can quickly return to your editcache extent at any time in youredit session. Click the Zoom toEdit Cache button on the EditCache toolbar.

Creating an edit cache

1. Add the data you want to edit.

2. Click the Zoom In button onthe Tools toolbar.

3. Zoom in to the area on themap that you want to edit.

4. Click the Build Edit Cachecache button on the EditCache toolbar.

The features visible in thecurrent extent are held inmemory locally.

Saving your edits in themiddle of an edit session

1. Click Editor.

2. Click Save Edits.

Any edits you have made aresaved to the database.

4

2

1

ch3.p65 01/10/2001, 10:38 AM62

EDITING BASICS 63

Stopping an edit session

1. Click Editor and click StopEditing.

2. To save changes, click Yes.To quit without saving, clickNo.

Tip

Editing in layout viewYou can also edit data in a map thatyou�re preparing. Click the Viewmenu and click Layout View. Formore information about working inlayout view, see �Editing in dataview and layout view� inChapter 1.

Tip

Editing a map with morethan one data frameIf your map contains more thanone data frame, you will be editingthe data frame that is active whenyou choose Start Editing. To edit adifferent data frame, you mustchoose Stop Editing and thenchoose Start Editing with thedesired data frame active.

For a discussion of data frames,see �Layers, data frames, and thetable of contents� in Chapter 3 ofUsing ArcMap.

1

2

ch3.p65 01/25/2001, 7:29 AM63


SelectingfeaturesSelecting features identifies thefeatures on which you want toperform certain operations. Forexample, before you move,delete, or copy a feature, youmust select it. You must alsoselect features before you canview their attributes.

You can select features inseveral different ways, either byclicking them with the Edit toolor by creating a line or apolygon that intersects thefeatures you want to select. Thenumber of features selected isshown immediately after youmake the selection, in the lower-left corner of the ArcMapwindow. u

Selecting features usingthe Edit tool

1. Click the Edit tool.

2. Move the pointer over afeature and click the mouse.

The selected feature ishighlighted.

The selected building is highlighted.

2

Tip

Selecting more than onefeatureTo select more than one feature,hold down the Shift key while youclick the features. You can also usethe Edit tool to drag a box arounda group of features.

Tip

Removing features fromthe selectionTo remove features from theselection set, hold down the Shiftkey while you click the features.

1

ch3.p65 01/10/2001, 10:39 AM64

EDITING BASICS 65

Selecting features usinga line

1. Click the Current Taskdropdown arrow and clickSelect Features Using a Line.

2. Click the tool palettedropdown arrow and clickthe Sketch tool or any of theother construction tools in thetool palette.

3. Construct a line that inter-sects the features you wantto select.

The features that the lineintersects are now selected.

Features intersected by the line are now selected.

3

The small �x� located in thecenter of the selected featuresis the selection anchor. Theselection anchor is used whenrotating features, moving featuresusing snapping, and scalingfeatures.

You can choose which layers youcan select by choosing SetSelectable Layers from theSelection menu and using theSelectable Layers list.

For example, suppose youwanted to select a large numberof buildings by drawing a boxaround them but selected a parcelby mistake as you drew the u

See Also

For more information on theselection anchor, see �Movingfeatures� in this chapter and�Scaling features� in Chapter 7.

Tip

Moving the selectionanchorTo move the selection anchor, movethe pointer over it, press the Ctrlkey, and drag the selection anchorto the desired location.

See Also

For more information on creatinga line, see �Creating lines andpolygons� in Chapter 4.

12

ch3.p65 01/25/2001, 7:29 AM65


Selecting features usinga polygon

1. Click the Current Taskdropdown arrow and clickSelect Features Using anArea.

2. Click the tool palettedropdown arrow and click theSketch tool or any of theother construction tools in thetool palette.

3. Construct a polygon thatintersects the features youwant to select.

The features that intersectwith the polygon you createdare now selected.

Features that intersect with the area are now selected.

3

selection box. To avoid this,you might uncheck the Parcelslayer in the Selectable Layerslist so that parcels cannot beselected. 1

2

See Also

For more information on creatinga polygon, see �Creating lines andpolygons� in Chapter 4.

See Also

For more information on selectingfeatures in ArcMap, includingselecting features for analysis, seeChapter 13, �Querying maps�, inUsing ArcMap.

Tip

Pan and zoom while youselect featuresYou can pan and zoom whileselecting features without having tochange tools. Hold the Control keyand press Z to zoom in, X to zoomout, or C to pan.

Tip

Use the Selection menu formore control over yourselectionThe Selection menu gives you moretools with which to make aselection, such as adding to thecurrent selection, selecting allfeatures onscreen, or creating anSQL statement.

ch3.p65 01/25/2001, 7:29 AM66

EDITING BASICS 67

Making a layer selectable

1. Click Selection and click SetSelectable Layers.

2. Click the check boxes next tothe layer names you want tobe able to select. Uncheckthe boxes next to the namesyou don’t want to be able toselect.

Layers whose names areunchecked are still visible inyour map but cannot beselected.

1

2

ch3.p65 01/25/2001, 7:30 AM67


Moving featuresYou can move features in threedifferent ways: by dragging; byspecifying delta x,y coordinates;or by rotating.

Dragging is the easiest way tomove a feature. Use this methodwhen you have a general idea ofwhere you want to move thefeature.

Specify delta x,y coordinateswhen you want to move a featureto a precise location. ArcMapuses the current location of theselected feature or features as theorigin (0,0) and moves themfrom that location according tothe coordinates you specify. u

Dragging a feature


2. Click the feature or featuresyou want to move.

3. Click and drag the feature orfeatures to the desiredlocation.

2

Tip

“Undoing” a moveYou can undo any edit you make toa feature by clicking the Undobutton on the ArcMap Standardtoolbar.

1

3

The selected building is dragged to a new location.

ch3.p65 01/10/2001, 10:40 AM68

EDITING BASICS 69

Moving a feature relativeto its current location


2. Click the feature or featuresyou want to move.

3. Click Editor and click Move. u

2

1

The coordinates are measured inmap units. The graphic belowillustrates the change in locationwhen delta x,y coordinates of 2,3are specified for a building.

In the example above, thebuilding is moved up and to theright, as positive coordinatevalues are specified. To move thebuilding left and down, youwould specify negative values.

You can rotate features inArcMap using the Rotate tool.After selecting the features, dragthe mouse pointer so that thefeatures rotate to the desiredposition. Features rotate aroundthe selection anchor, the small�x� located in the center ofselected features.

If you want to move a feature toa precise location in relation toanother feature, you can use thesnapping environment. Forexample, you can move a u

(0,0)

(2,3)

3

ch3.p65 01/25/2001, 7:30 AM69


The feature is moved 40 map units to the left.

4. Type the desired coordinatesand press Enter.

The feature is movedaccording to the specifiedcoordinates.

parcel and have one of itscorners jump, or �snap�,precisely to a corner of anotherparcel. Simply move the parcel�sselection anchor to its cornervertex after setting the appro-priate snapping properties.Then, move the parcel towardits new location until theselection anchor snaps to thecorner vertex of the otherparcel. Snapping is discussed indetail in Chapter 4, �Creatingnew features�.

Tip

Moving the selectionanchorTo move the selection anchor, movethe pointer over it, press the Ctrlkey, and drag the selection anchorto the desired location.

4

ch3.p65 01/10/2001, 10:40 AM70

EDITING BASICS 71

Rotating a feature


2. Click the feature or featuresyou want to rotate.

3. Click the Rotate tool.

4. Click anywhere on the mapand drag the pointer to rotatethe feature to the desiredposition.

The selected features are rotated.

2

1

3

Tip

Rotating a point’ssymbologyIf your data already has a fieldthat contains the rotation angle foreach point symbol, you can useArcMap to rotate the symbology.

Right-click the point layer name inthe map�s table of contents andclick Properties.Click the Symbol-ogy tab. Click the Advancedbutton,then click Rotation. Fromthe dropdown list, choose the fieldthat contains the rotation angle.Click the option that describes howyou want that angle calculated.

Tip

Rotating by degreeTo specify the exact amount ofcounterclockwise rotation, click theRotate tool, press A, and type thenumber of degrees. A positivenumber rotates the feature to theright, a negative number to theleft.

ch3.p65 01/25/2001, 7:30 AM71



2. Click the feature or featuresyou want to delete.

3. Click the Delete button on theArcMap Standard toolbar.

The selected features aredeleted.

Deleting featuresTo delete a feature from the mapand from the database, use theDelete button on the ArcMapStandard toolbar.

Tip

Deleting features using theDelete keyYou can also press the Delete keyon the keyboard to remove selectedfeatures.

The selected building is deleted.

1

2

3

ch3.p65 01/10/2001, 10:41 AM72

EDITING BASICS 73

Copying andpasting featuresTo copy an existing feature,use the tools on the ArcMapStandard toolbar. From theTarget layer dropdown list,choose the layer containing thetype of features you want thenew feature to be�for example,a building.

You can copy a feature andpaste it as part of another layer,but it must be the same type oflayer (point, line, or polygon) asthe one from which you copied.There is one exception to thisrule�you can copy polygonsinto a line layer.

Attributes from the originalfeature are only copied to thenew feature if you are copyingand pasting within the samelayer.

1. Click the Target layerdropdown arrow and click thelayer containing the type offeatures you want the newfeatures to be.


3. Click the feature or featuresyou want to copy.

4. Click the Copy button on theArcMap Standard toolbar.

5. Click the Paste button on theArcMap Standard toolbar.

The feature is pasted on topof the original feature.

3

2

1

54See Also

For more information on at-tributes, see Chapter 9, �Editingattributes�. You can also seeChapter 10 of Using ArcMap.

The selected feature is pasted on top of the original feature.

ch3.p65 01/25/2001, 7:30 AM73


Setting thenumber ofdecimal placesused for reportingmeasurementsWhen creating or editing afeature with the Sketch tool, youcan use the Sketch tool contextmenu to view such measurementsas the distance between twovertices, the angle between twosegments, or the current coordi-nate location of the pointer.

By default, ArcMap displaysthese measurements using fourdecimal places. However, youcan easily change the number ofdecimal places displayed. Afteryou set the number of decimalplaces, ArcMap will report allmeasurements using that numberof decimal places.

1. Click Editor and click Op-tions.

2. Click the General tab.

3. Type the number of decimalplaces you want to use.

4. Click OK.

1

3

2

4

ch3.p65 01/10/2001, 10:41 AM74

IN THIS CHAPTER

75

Creating new features 4• How to create a new feature

• Creating point features andvertices

• Creating lines and polygons

• Creating segments using anglesand lengths

• Creating segments using anglesfrom existing segments

• Creating segments that areparametric curves

• Using the snapping environment

It�s easy to create new features using the editing sketch construction tools.First, specify the layer in which you want to create the new feature. Then,use the appropriate tool to digitize the vertices of the feature.

You can use the editing tools to create new point, line, or polygon featuresfor many practical purposes. Use the Sketch tool and its accompanyingcontext menu to add a water main perpendicular to an existing water main ina subdivision. Use the Distance�Distance tool to create a land parcel thatbegins 55 meters from one corner of an existing lot and 40 meters fromanother lot corner. Create a cul-de-sac using the Arc tool to create aparametric (true) curve. With the Intersection tool, add a parcel to asubdivision by establishing a corner vertex using segments of an adjoiningparcel.

Using the editing tools, you can create a variety of features by constructingsegments at specific angles and of specific lengths. You can create featuresthat are parallel or perpendicular to other features. You can also createmultipoint features, such as a system of oil wells, and multipart features,such as a group of islands that form a country or state.

These are just a few examples of how you can use ArcMap to easily andaccurately create new features for your database.

ch4.p65 01/10/2001, 10:44 AM75


A sketch is composed of vertices (the points at which the sketchchanges direction such as corners) and segments (the lines thatconnect the vertices). You create a sketch using the Sketch toollocated on the tool palette.

To create point features, click once on the map. To create line orpolygon features (see the example below), use the Sketch tool toclick on the map to digitize the vertices that make up that feature.To create the last vertex and finish the sketch, double-click withthe mouse. After you finish the sketch, ArcMap adds the finalsegment of the sketch and the sketch turns into a feature.

To create a new feature using ArcMap, you create an edit sketch.A sketch is a shape that you draw by digitizing vertices. You canuse a sketch to complete various tasks; these tasks are listed inthe Current Task dropdown list shown below. Tasks you cancomplete with a sketch include creating new features, modifyingfeatures, extending or trimming features, and reshaping features.

This chapter focuses on using sketches to create new features.When the current task setting is Create New Feature, the shapeyou create becomes the new feature.

Building as sketch Building as feature

3. Click hereto place thethird vertex.

2. Click hereto place thesecondvertex.

1. Click hereto place thefirst vertex.

4. Double-clickhere to place

the last vertexand finish the

sketch.

How to create a new feature

Current Task dropdown list

Sketch tool Toolpalette

ch4.p65 01/10/2001, 10:44 AM76

CREATING NEW FEATURES 77

The type of feature you create is determined by the setting of theTarget layer dropdown list. This list contains the names of all thelayers in the datasets with which you�re working.

Choose the layer to which you want to add new features beforeyou start to create them.

Of course, you won�t always be able to place vertices orsegments interactively. When you�re using the Sketch tool, youcan see a menu called the Sketch tool context menu. You canaccess this menu when you right-click the mouse away from thesketch you�re creating. The menu has choices to help you placethe vertices and segments exactly where you want them. Forexample, you can set a segment to be a certain length or angle orcreate a vertex at a specific x,y coordinate location.

Target layer dropdown list

Sketch tool context menu

ch4.p65 01/10/2001, 10:44 AM77


All the tools on the tool palette help you create a sketch. Twotools use more specific construction methods to create eitherpoints or vertices: the Distance�Distance tool and theIntersection tool.

The Distance�Distance tool lets you create a point or vertex atthe intersection of two distances from two other points. Youmight use this tool to place a new electrical primary based onfield measurements. Suppose you know that the next point for theprimary is 50 feet from one building corner and 75 feet fromanother.

The Distance–Distance tool gives the intersection points of two circles;the size of the circles is determined by the radius you set.

The Distance�Distance tool creates two circles based on thesedistances and finds two possible intersection points where theprimary can be placed.

The Intersection tool creates a point or vertex at the place wheretwo segments would intersect if extended far enough. Supposeyou want to create a parking lot adjoining an L-shaped building.The outer corner of the lot should be located at the point wherethe two outermost walls of the building would intersect if theywere extended. You could use the Intersection tool to find this�implied� intersection point and create the corner vertex of thelot (see graphic below).

The Intersection tool creates a vertex here—at the place where the two segments would intersect.

Intersectiontool

Distance–Distancetool

Sketch tool

Arc tool

Trace tool

ch4.p65 01/10/2001, 10:45 AM78


The Arc tool helps you create a segment that is a parametric (true)curve.

The Trace tool helps you create segments that follow alongexisting segments. Suppose you want to add a new road casingfeature that is offset 15 feet from the front of a parcelsubdivision. You could use the Trace tool to trace along theexisting line features instead of typing the angle and length ofeach segment.

1. Clickonce toestablishthestartpoint.

2. Click here to establishthe axis. This is theinvisible point throughwhich the curve passes.

3. Clickhere to

establishthe

endpoint.

You can use any combination of the following methods forcreating vertices or segments to create a new line or polygonfeature:

� Sketch tool

� Sketch tool context menu

� Distance�Distance tool

� Intersection tool

� Arc tool

� Trace tool

ArcMap has another context menu�the Sketch context menu�that works more directly with the sketch as a whole. With thismenu, you can add, move, or delete vertices; switch the directionof the sketch; reduce its length; or display the properties of thesketch shape. From the properties dialog box, you can removeparts from a multipart feature, remove many vertices in oneoperation, add points, and/or modify m- and z-values. The Sketchcontext menu is available when you right-click while the pointeris positioned over any part of the sketch using any tool. It differsfrom the Sketch tool context menu, which you can access onlywhen working with the Sketch tool and when you right-clickaway from your sketch.

1. Press O toset the offsetvalue.

2. Click here tostart tracing.

3. Followalong thefeature totrace.

Sketch context menu

ch4.p65 01/10/2001, 10:45 AM79


Creating pointfeatures andverticesYou can think of vertices asbeing much the same as pointfeatures, except that vertices areconnected by segments and makeup line or polygon features.

Point features and vertices arecreated using the same methods.The Target layer setting deter-mines whether you�re creating apoint feature or a vertex that ispart of a line or polygon sketch.

You can create point features orvertices of a sketch in severaldifferent ways:

� By digitizing freehand withthe Sketch tool (you can alsouse the snapping environmentto help)

� By using Absolute X, Y orDelta X, Y on the Sketch toolcontext menu u

Creating a point or vertexby digitizing

1. Click the Current Taskdropdown arrow and clickCreate New Feature.

2. Click the Target Layerdropdown list and click apoint layer.

3. Click the tool palettedropdown arrow and click theSketch tool.

4. Click on the map to create thepoint.

The point or vertex is createdon your map and marked asselected.

Suppose you wantto create a point here.

A new point featureis created.

3

1

2

Tip

The snapping environmentcan help you create pointsand verticesThe snapping environment canhelp you create points or vertices atmore exact locations relative toother features. For more informa-tion, see �Using the snapping envi-ronment� in this chapter.

ch4.p65 01/10/2001, 10:45 AM80


Creating a point or vertexusing the coordinatesystem of the map(Absolute X, Y)

1. Click the tool palettedropdown arrow and clickthe Sketch tool.

2. Right-click anywhere on themap and click Absolute X, Y.

3. Type the coordinates andpress Enter.

A vertex or point is created atthe specified coordinates.

3

� By using the Distance�Distance or Intersection tools

To digitize freehand, simply clickthe Sketch tool and click on themap.

Absolute X, Y on the Sketch toolcontext menu lets you create apoint or vertex using the origin(0,0) of the map�s coordinatesystem. In other words, thelocation of the point or vertexyou�re creating is determinedusing the same point for 0,0 asyour map data. You might useAbsolute X, Y to create a pole ina utility database if you have thex,y coordinates of a pole fromusing a global positioning system(GPS) unit. u

Tip

Closing the Sketch toolcontext menuYou can close the Sketch tool con-text menu by pressing the Esc key.

A point is createdat (2222264,394370).

1

2

Tip

Shortcut for Absolute X, YAfter clicking the Sketch tool, youcan press F6 to set the x,y coordi-nates.

ch4.p65 01/10/2001, 10:45 AM81


Creating a vertex relativeto the location of the lastvertex (Delta X,Y)

1. Click the tool palettedropdown arrow and click theSketch tool after creating atleast one vertex.

2. Right-click away from thevertex or sketch and clickDelta X, Y.

3. Type the coordinates andpress Enter.

A vertex is created at thespecified coordinates.

Tip

Shortcut for Delta X, YAfter clicking the Sketch tool, youcan press Ctrl + D to set the deltax,y coordinates.

Delta X, Y on the Sketch toolcontext menu lets you create avertex using the last vertex in thesketch as the origin. You canthink of it as another way ofmeasuring angle and length froma point already on the map.

For example, just as the redpoint in the diagram below canbe measured at a distance of20 feet from the last point at anangle of 45 degrees, it can alsobe measured in coordinatesmeasured from the last point. u

1

3

2

(0,0)(270,40)

A vertex iscreated at(270,40).

Same point measured using deltax,y coordinates

45°

Point measured using an angle andlength

20 ft.

4

3

(0, 0)

(3, 4)

ch4.p65 01/10/2001, 10:46 AM82


Creating a point or vertexusing the Distance–Distance tool

1. Click the tool palettedropdown arrow and clickthe Distance–Distance tool.

2. Click once to establish thecenterpoint of the first circleand press the letter D on thekeyboard.

3. Type the radius length for thefirst circle and press Enter.

A circle is created with thespecified radius. u

2

3

A circle with a 50-mapunit radius is created.

The Distance�Distance tooloffers another way to create apoint or vertex at a specificlocation. Suppose you want tocreate a pole feature. If youdon�t have the exact coordinatelocation but know that it is atthe intersection of 50 map unitsfrom the corner of one buildingand 70 map units from thecorner of another, you can usethe Distance�Distance tool toplace the point. The Distance�Distance tool lets you create apoint or vertex at the intersec-tion of two distances from twoother points.

As shown in the example, you�dcreate one circle with thecenterpoint on the corner of thefirst building and a radius of50 map units. You�d createanother circle with thecenterpoint on the corner of theother building and a radius of70 map units. The Distance�Distance tool calculates the twolocations where the radii of thecircles intersect.

The Intersection tool creates apoint or vertex at the impliedintersection of two segments.�Implied� means that thesegments don�t have to actuallyintersect on the map. TheIntersection tool creates a pointor vertex at the place where thesegments would intersect ifextended far enough.u

1

ch4.p65 01/10/2001, 10:46 AM83


Tip

Choosing an intersectionpointPress Tab to alternate between thetwo points of intersection andpress Enter to create the point.

5

4

A circle with a 70-map unitradius is created.

6

A point is created at one oftwo places where the radii ofthe circles intersect.

For example, suppose you wantto create a new parcel. Onecorner of the parcel must beplaced at the implied intersectionof two segments of an adjoiningparcel. You can use the Inter-section tool to find this impliedintersection point and create thecorner vertex of the new parcel.

You can also create amultipoint feature, a featurethat consists of more than one u

4. Click once to establish thecenterpoint of the secondcircle and press the letter Don the keyboard.

5. Type the radius length for thesecond circle and pressEnter.

A second circle is createdwith the specified radius. Thetwo locations where the radiiof the circles intersect arehighlighted when you movethe pointer over them.

6. Position the pointer over thelocation you want and click.

A vertex or point is added toyour map.

Tip

“Undoing” and “redoing” avertexYou can undo any vertex you cre-ate by clicking the Undo button onthe ArcMap Standard toolbar.Click the Redo button if you wantto readd the vertex.

ch4.p65 01/10/2001, 10:47 AM84


Creating a point or vertexusing the Intersectiontool

1. Click the tool palettedropdown arrow and click theIntersection tool.

The pointer turns intocrosshairs.

2. Position the crosshairs overthe first segment and click.

3. Position the crosshairs overthe second segment andclick.

A vertex or point is added atthe implied intersection of thetwo segments.

A vertex is added at the place wherethe two segments would intersect if extended.

2

3

point but only references oneset of attributes in the data-base. A system of oil wells is anexample of a multipoint feature;the database references a singleset of attributes for the mainwell and the multiple well holesin the system.

To create new features, youmust have an existing layer towhich you want to add them. Ifyou do not, you can create oneusing ArcCatalog�. For moreinformation on creating afeature layer, see UsingArcCatalog.

Tip

Pan and zoom while addingpointsHold down the Control key andpress Z to zoom out, X to zoom in,or C to pan the display when usingany sketch tool.

1

ch4.p65 01/10/2001, 10:47 AM85


Creating a multipointfeature


2. Click the Target layerdropdown arrow and click amultipoint layer.


4. Click on the map to createparts of the multipointfeature.

5. When you have created thelast point of the multipointfeature, right-click anywhereon the map and click FinishSketch. u

5

3

1 2

ch4.p65 01/10/2001, 10:48 AM86


Now, when you click one partof the multipoint feature toselect it, all points areautomatically selectedbecause they all belong toone multipoint feature.

All points of the feature are selected.

ch4.p65 01/10/2001, 10:48 AM87


Creating a line or polygonfeature by digitizing


2. Click the Target layerdropdown arrow and click aline or polygon layer.


4. Click on the map to digitizethe feature’s vertices.

5. When finished, right-clickanywhere on the map andclick Finish Sketch. u

Creating linesand polygonsYou can create lines or poly-gons by digitizing the verticesthat make up the feature. Forexample, to create a squarebuilding, you would digitize thefour corners. Use any combina-tion of methods for creatingvertices or segments. u

Tip

Deleting the sketchTo delete the entire sketch of thefeature you�re creating, positionthe pointer over any part of thesketch, right-click, and click DeleteSketch. You can also delete asketch by pressing Ctrl + Num Del.

Tip

Deleting a vertexTo delete a single vertex from asketch, center the pointer over thevertex until the pointer changes.Right-click, then click Delete Ver-tex.

Tip

Shortcut for finishing thesketchYou can double-click on the lastvertex of the feature to finish thesketch. Or, press F2 when you�vefinished creating the sketch.

1

2

3

5

ch4.p65 01/10/2001, 10:48 AM88


The Square and Finish com-mand on the Sketch tool contextmenu is a way of completing apolygon. It finishes a polygonby adding two new segments at90-degree angles. Square andFinish saves you time andensures precision whencreating square-corneredbuildings.

ArcMap also provides a way tocreate a multipart feature, afeature that is composed of morethan one physical part but onlyreferences one set of attributes inthe database. For example, theState of Hawaii could beconsidered a multipart feature.Although composed of manyislands, it would be recorded asone feature. A multipart featurecan only share vertices, notedges.

The line or polygon iscreated on your map.

Tip

“Undoing” and “redoing” avertexYou can undo the last vertex youcreated by clicking the Undo but-ton on the ArcMap Standardtoolbar. Click the button again toundo the second-to-last vertex youcreated, and so on. Click the Redobutton if you want to readd thevertex.

A new feature is createdon your map.

ch4.p65 01/10/2001, 10:48 AM89


Creating a multipart lineor polygon

1. Create a line or polygonfeature.

2. When finished creating thefirst part of the feature, right-click anywhere on the mapand click Finish Part.

3. Create the next part of thefeature.

4. When you have finished thelast part of the feature, right-click anywhere on the mapand click Finish Sketch. u

Tip

StreamingYou can also create lines and poly-gons with the mouse using streammode digitizing (streaming). Formore information, see Chapter 5,�Using a digitizer�.

Tip

Shortcut for finishing apartYou can hold down the Shift keyand double-click on the last vertexof a part to finish it.

Tip

Shortcut for finishing thesketchYou can double-click on the lastvertex of the new feature to finishthe sketch.

Tip

Replace sketchYou can add the shape of a line orpolygon feature to the sketch byright-clicking over the feature withthe Sketch tool and clicking Re-place Sketch. The sketch will con-tain the shape of the feature youclicked over.

2

1

3

4

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Both parts of the feature are selected.

Now when you click one partof the feature to select it, allparts are automaticallyselected because they allbelong to one multipartfeature.

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Squaring a polygon orpolyline


2. Click the Target layerdropdown arrow and click apolygon or polyline layer.


4. Digitize at least two seg-ments.

5. Right-click anywhere awayfrom the sketch and clickSquare and Finish. u

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The angles from the firstvertex and the last vertex aresquared. A new vertex isadded, and the sketch isfinished where the resultingsegments intersect.

firstvertex

lastvertex

newvertex

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Creatingsegments usingangles andlengthsThe edit tools help you createsegments at specific angles,measured either using the mapcoordinate system (Angle) orfrom the last segment (Deflec-tion).

The Angle command uses east as0 degrees and measures positiveangles counterclockwise. Forexample, a 90-degree anglerepresents north and a 180-degree angle represents west.

The Deflection command usesthe last segment as 0 degrees andcalculates the angle you specifyfrom there. Positive values arecalculated in a counterclockwisedirection from the existingsegment, while negative valuesare calculated clockwise. Youmight use Deflection to createthe bent end of a water or gasline at a 33-degree angle to ahouse. u

Creating a segment usingan angle and a length


2. Right-click away from thesketch and click Angle.

3. Type the angle and pressEnter.

The segment is constrainedto the specified angle. u

Tip

Shortcut for angleAfter clicking the Sketch tool andcreating at least one vertex, youcan press Ctrl + A to set the angle.

1

3Angle constrained to 105 degrees

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Tip

Shortcut for lengthAfter clicking the Sketch tool andcreating at least one vertex, youcan press Ctrl + L to set the length.

Tip

Specifying angle andlength at the same timeChoose the Angle/Length commandfrom the Sketch tool context menu.After clicking the Sketch tool andcreating at least one vertex, youcan press Ctrl + G to set the angleand length.

Tip

Changing the length of asegmentIf you want to change the length ofa segment you have already cre-ated, you can use Change Lengthon the Sketch tool context menu.This undoes the last vertex whilekeeping the angle constraint.

When using the Sketch tool, youcan press F5 to undo the last vertexwhile keeping the angle constraint.

The vertex that makes the segment the desiredangle and length is created.

4. Right-click anywhere on themap and click Length.

5. Type the length and pressEnter.

The vertex that makes thesegment the desired angleand length is created.

Both the Angle and Deflectioncommands constrain the angle ofthe segment. For example, if youtype �45� as the angle, thesegment will be constrained to a45-degree angle one way and a225-degree angle the other.

Use the Length command tospecify the length of a segmentyou�re creating.

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Creating a segment at anangle from the lastsegment (deflection)

1. Click the tool palettedropdown arrow and click theSketch tool after creating atleast one vertex for the newsegment.

2. Right-click away from thesketch.

3. Click Deflection.

4. Type the desired angle fromthe last segment and pressEnter. u

Tip

Shortcut for deflectionAfter clicking the Sketch tool andcreating at least one vertex, youcan press Ctrl + F to set the de-flection angle.

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The segment is constrainedto the specified angle.

5. Click once to digitize theendpoint of the segment orchoose Length from theSketch tool context menu.

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Creating a segment at anangle from any othersegment


2. Position the pointer over thesegment from which you wantto create a segment andright-click with the mouse.

3. Click Segment Deflection.

4. Type the desired angle fromthe segment you chose andpress Enter. u

Creatingsegments usingangles fromexistingsegmentsThree commands on the Sketchtool context menu�SegmentDeflection, Parallel, and Perpen-dicular�help create segmentswith angles relative to segmentsthat already exist.

The Segment Deflection com-mand lets you create a segment atan angle relative to any existingsegment. While Deflectioncreates a segment at a specificangle from the last segment inthe feature you�re creating,Segment Deflection lets youchoose which segment you wantto work from�it need not be thelast segment.

As with the Deflection com-mand, the segment you work u

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Tip

Shortcut for segmentdeflectionAfter clicking the Sketch tool, cre-ating at least one vertex, and posi-tioning the pointer over the seg-ment from which you want to bethe specific angle, you can pressF7 to set the angle.

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from with Segment Deflection is0 degrees, and the deflectionangle you specify for the newsegment is calculated from there.Positive values are calculated ina counterclockwise directionfrom the existing segment, whilenegative values are calculatedclockwise. The example givenshows a cross street created at a-45-degree angle to the existingstreets.

The Parallel command on theSketch tool context menuconstrains a segment to beparallel to any segment youchoose. For instance, you mightuse this command to create a gasmain line parallel to the street.

The Perpendicular command onthe Sketch tool context menuconstrains a segment to beperpendicular to an existingsegment. You might use thiscommand to place a service lineperpendicular to the main line.

The segment is constrainedto the specified angle.


Tip

Using only positive valueswith segment deflectionIf you wish to work only with posi-tive angle values, convert negativeangles to positive angles by adding180 to the negative value. Forexample, a -45-degree angle (mea-sured clockwise) becomes a 135-degree angle (measured counter-clockwise).

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Creating a segmentparallel to anothersegment


2. Position the pointer over thesegment to which the newsegment will be parallel andright-click.

3. Click Parallel.

The segment is constrainedto be parallel to the specifiedsegment.


Tip

Shortcut for parallelAfter clicking the Sketch tool,creating at least one vertex, andpositioning the pointer over thesegment to which the new segmentwill be parallel, you can pressCtrl + P to make the segmentparallel.

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Creating a segmentperpendicular to anothersegment

1. Click the tool palettedropdown arrow and clickthe Sketch tool after creatingat least one vertex.

2. Position the pointer over thesegment to which the newsegment will be perpendicu-lar and right-click with themouse.

3. Click Perpendicular.

The segment is constrainedto be perpendicular to thespecified segment.


Tip

Shortcut for perpendicularAfter clicking the Sketch tool, cre-ating at least one vertex, and posi-tioning the pointer over the seg-ment to which the new segmentwill be perpendicular, you canpress Ctrl + E to make the segmentperpendicular.

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Creatingsegments thatare parametriccurvesWhen creating features, it isoften necessary to create aparametric (true) curve.Instead of being made ofnumerous vertices, a parametriccurve has only two vertices asendpoints. ArcMap offers twoways to create a segment that isa parametric curve.

First, you can create a paramet-ric curve using the Arc tool.You might use the Arc tool todigitize a cul-de-sac using anaerial photo image as a back-drop.

You can also create a parametriccurve using the Tangent Curvecommand on the Sketch toolcontext menu. You can use theTangent Curve command to adda parametric curve to an existingsegment. For example, youmight use this command to adda curved segment to extend acenterline along a curved road.

When you create a tangentcurve, you must specify twoparameters for the curve fromthe following options: arclength, chord, radius, or deltaangle. You must also specifywhether you want to create u

Creating a segment thatis a parametric curveusing the Arc tool

1. Click the tool palettedropdown arrow and click theArc tool.

2. Click once to establish thestartpoint of the arc.

A vertex is created.

3. Click once to establish theaxis of the arc.

This is the invisible pointthrough which the curvepasses.

4. Click once to establish theendpoint of the arc.

A segment that is a true curveis created.

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A segment that is a true curve is created.

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Creating a segment thatis a parametric curveusing the Tangent Curvecommand

1. Click the tool palettedropdown arrow and click theSketch tool after creating atleast one segment.

2. Right-click anywhere on themap and click Tangent Curve.

3. Click the dropdown arrowsand click two parameters bywhich you want to define thecurve.

4. Type the appropriate valuesfor the parameters (distancein map units for arc length,chord, and radius; degreesfor delta angle).

5. Click Left to create thetangent curve to the left ofthe segment. Click Right tocreate the curve to the right.

6. Press Enter. u

the curve to the right of the lineor to the left of the line,according to the direction inwhich the line was drawn. Thecurve is created from the lastvertex of the existing segmentbased on the parameters youdefined.

If you choose chord length andradius to construct the curve,there are two possible solutions�the major and minor portionsof the circle.

The Minor check box willappear at the bottom of theTangent Curve dialog box.Check it to construct the minorportion of the circle.

Major

Minor

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A segment that is a true curveis created from the last vertexof the segment according tothe parameters you specified.

A parametric curve with a chord length of 80 map units and a deltaangle of 70 degrees is created to the left of the last vertex.

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Creating segments bytracing features


2. Select the features that youwant to trace.

3. Click the tool palettedropdown arrow and click theTrace tool.

4. Press O to set an offsetvalue. Type an offset valueand press Enter. Setting anoffset value is optional. If youwant to trace directly on topof existing features, enter avalue of 0.

5. Click to start tracing.

6. Click to stop tracing.

Creatingsegments bytracing featuresYou can create segments bytracing over the segments ofselected features using the Tracetool.

Suppose you want to create anew water main that is offset7 meters from the parcel bound-aries. Using the Trace tool, youcan create new segments in thesketch that are at the same angleas the selected parcel boundariesyet constructed at an offset valueof 7 meters.

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Tip

Backing up a traceIf you traced too far or have tracedthe wrong direction, move themouse backwards over what youhave traced. If you have clicked tostop the trace, click Undo to re-move all vertices added during thetrace.

Tip

Canceling a traceA quick way to cancel a trace is toPress the Esc key.

Tip

Finish the sketchWhen you are finished tracing, youcan double-click to finish thesketch.

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The Snapping Environment window

The layers in your mapdocument are listed here.

Set the snapping priority—the order in which snapping

will occur by layer—bydragging the layer

names to new locations.

Check the type of snappingproperties you want for eachlayer.

The bottom portion of thewindow shows snapping

properties that work with asketch.

You can keep the windowopen as you work—any changes in settingsare effective immediately.Click the Close button whenyou are finished.

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Types of snapping properties

Layer snapping properties Sketch snapping properties

Vertex Snaps to each vertex of the features in Perpendicular to sketch Lets you create a segmentthat layer. that will be perpendicular to

the previous.

Edge Snaps to the entire outline (both segments Edit sketch vertices Snaps to the vertices of theand vertices) of each feature in that layer. sketch.

Endpoint Snaps to the first vertex and the last vertex in a Edit sketch edges Snaps to the entire outlineline feature. (both segments and

vertices) of the sketch.

When you use the snapping environment to create or place a new feature in an exact location relative to other features, you must chooseto which part of existing features�vertex, edge, or endpoint�you want your feature to snap. These choices are called layer snappingproperties. You can also specify snapping properties for the edit sketch itself; these are called sketch snapping properties. You can setboth types of snapping properties using the Snapping Environment window. The following table briefly explains each of the layersnapping and sketch snapping properties.

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Using thesnappingenvironmentThe snapping environment canhelp you establish exact locationsin relation to other features.Suppose you�re creating a newsegment of primary that beginsfrom an existing transformer; youwant to ensure that the vertex ofthe primary connects precisely tothe transformer.

The snapping environment makesthis type of task accurate andeasy. Setting the snappingenvironment involves setting asnapping tolerance, snappingproperties, and a snappingpriority.

The snapping tolerance is thedistance within which the pointeror a feature is snapped to anotherlocation. If the location beingsnapped to (vertex, edge, orendpoint) is within the distanceyou set, the pointer automaticallysnaps (jumps) to the location. u

Tip

Viewing the snappingtoleranceTo see the current snapping toler-ance, hold down the T key whileusing the Sketch tool.

Setting the snappingtolerance

1. Click Editor and clickOptions.


3. Click the Snapping tolerancedropdown arrow and clickthe type of measurement unityou want to use for thesnapping tolerance—pixelsor map units.

4. Type the desired number ofmeasurement units in theSnapping tolerance text box.

5. Click OK.

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The circle around the pointer inthe graphics below represents thesnapping tolerance. When thelocation being snapped to(orange point) is outside thesnapping tolerance, the snappinglocation (blue dot) stays with thepointer (top graphic). When thelocation being snapped to isinside the snapping tolerance, thesnapping location moves awayfrom the pointer and snaps to thetarget location (bottom graphic).

You can choose the part of thefeature�vertex, edge, orendpoint�to which you wantyour new feature to snap bysetting the layer snappingproperties. For example, if youwant your new feature�asegment of primary�to snap tothe vertex of an existing trans-former in the transformers layer,you would check the box underVertex and next to the transform-ers layer in the SnappingEnvironment window. When u

Setting snappingproperties

1. Click Editor and click Snap-ping.

The Snapping Environmentwindow appears.

2. Check the snapping proper-ties you want.

The snapping properties areeffective as soon as they arechecked or unchecked.

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the pointer comes within thesnapping tolerance of thetransformer, the first vertex of theprimary snaps to the vertex of thetransformer.

You can also set the snappingpriority for layers on your map.The order of layers listed in theSnapping Environment windowdetermines the order in whichsnapping will occur. Snappingoccurs first in the layer at the topof the list and then in eachconsecutive layer down the list.You can easily change thesnapping priority by dragging thelayer names to new locations.

Tip

Sketch snappingpropertiesYou can set snapping propertiesthat apply specifically to an editsketch in the Snapping Environ-ment dialog box as well; these arelocated at the bottom of the Snap-ping Environment window. Formore information, see �Types ofsnapping properties� in this chap-ter.

Setting the snappingpriority

1. Click Editor and click Snap-ping.

The Snapping Environmentwindow appears.

2. Click and drag the layernames to arrange them in theorder in which you wantsnapping to occur. (The firstlayer in the list will besnapped to first.)

The snapping priorities youset are effective immediately.

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IN THIS CHAPTER

111

Using a digitizer 5• Setting up your digitizing tablet

• Preparing your paper map fordigitizing

• Registering your paper map

• Creating features using a digitizer

• Digitizing features in point mode

• Digitizing features in stream mode

Digitizing is the process of converting features on a paper map into digitalformat. To digitize a map, you use a digitizing tablet connected to yourcomputer to trace over the features that interest you. The x,y coordinates ofthese features are automatically recorded and stored as spatial data.

Digitizing with a digitizing tablet offers another way, besides digitizing�freehand�, to create and edit spatial data. You can convert features fromalmost any paper map into digital features. You can use a digitizer inconjunction with the tools in ArcMap to create new features or edit existingfeatures on a digital map.

You may want to digitize features into a new layer and add the layer to anexisting map document, or you may want to create a completely new set oflayers for an area for which no digital data is available. You can also use adigitizer to update an existing layer on your digital map.

Chapter 4, �Creating new features�, introduced you to the Sketch tool andother useful editing tools in ArcMap and discussed how these are used todigitize features freehand. This chapter will teach you the fundamentals ofediting features in ArcMap using a digitizer. You may want to read Chapter 4first to get an understanding of editing before reading this chapter.

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Setting up your digitizing tablet and preparing your paper map

Before you can start digitizing, you must set up your digitizingtablet and prepare your paper map. This can be done after youhave installed the digitizer driver software.

Installing the driver software and configuringpuck buttons

To use a digitizing tablet with ArcInfo, it must have WinTab�-compliant digitizer driver software. To find out if a WinTab-compliant driver is available for your digitizer, see thedocumentation that came with the tablet or contact themanufacturer.

After installing the driver software, use the WinTab managersetup program to configure the buttons on your digitizer puck.(You may have to turn on your digitizer and reboot your machinebefore you can use the setup program.) One puck button shouldbe configured to perform a left mouse click to digitize pointfeatures and vertices; another button should be configured toperform a left double-click to finish digitizing line or polygonfeatures.

With any development programming language, you can configureadditional buttons to run specific ArcMap commands�such asthe Zoom In or Sketch tools�normally accessed through toolbarbuttons and menus. Exploring ArcObjects contains sample VisualBasic® for Applications (VBA) code that you can use to run avariety of ArcMap commands from the digitizer puck.

Preparing the map

After you have set up your digitizing tablet and configured thepuck buttons, you can prepare your paper map for digitizing.Your map should ideally be reliable, up-to-date, flat, and not tornor folded. Paper expands or shrinks according to the weather. Tominimize distortion in digitizing, experienced digitizers oftencopy paper maps to a more stable material such as Mylar®.

If you know what coordinate system (projection) your paper mapis in, you should set the same projection for the layer you�redigitizing into. If you are digitizing features into an existingfeature layer, you must ensure that your paper map and digitallayer share the same coordinate system. For more information onspecifying a coordinate system in ArcMap, see Chapter 4,�Creating maps�, in Using ArcMap.

Establishing control points on your paper map

Before you can begin digitizing from your paper map, you mustfirst establish control points that you will later use to register themap to the geographic space in ArcMap. If your map has a gridor a set of known ground points, you can use these as yourcontrol points. If not, you should choose between four andten distinctive locations such as road intersections and markthem on your map with a pencil. Give each location a uniquenumber and write down its actual ground coordinates.

Once you�ve identified at least four well-placed control points,you can place your map on the tablet and attach it with maskingtape. You don�t have to align the map precisely on your tablet;ArcMap corrects any alignment problems when you register themap and displays such adjustments in the error report.

The error report includes two different error calculations: a point-by-point error and a root mean square (RMS) error. The point-by-point error represents the distance deviation between thetransformation of each input control point and the correspondingpoint in map coordinates. The RMS error is an average of thosedeviations. ArcMap reports the point-by-point error in currentmap units. The RMS error is reported in both current map unitsand digitizer inches. If the RMS error is too high, you canreregister the appropriate control points. To maintain highlyaccurate data, the RMS error should be kept under 0.004 digitizerinches. For less accurate data, the value can be as high as0.008 digitizer inches.

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USING A DIGITIZER 113

Registering yourpaper mapBefore you can start digitizing,you must register your paper mapinto real-world coordinates. Thisallows you to digitize featuresdirectly in geographic space.

Registering your map involvesrecording the ground coordinatesfor the control points youidentified while preparing yourmap. These are recorded usingthe Digitizer tab of the EditingOptions dialog box. You mustfirst use the digitizer puck todigitize the control points on thepaper map; with the puck overeach control point on the map,press the button you configuredto perform a left mouse click.You must then type the actualground coordinates for eachcontrol point.

When registering your map, youhave the option of saving theground coordinates you enteredfor later use�for example, if youwant to reregister your map orregister another map that uses thesame control points. These u

Registering your map forthe first time

1. After adding a layer to yourmap, click the Editor menuand click Start Editing.

2. Click Editor and click Options.

3. Click the Digitizer tab.

4. With the digitizer puck,digitize the control points youestablished earlier on yourpaper map.

A record appears in the XDigitizer and Y Digitizercolumns for each controlpoint you digitized.

5. Type the actual groundcoordinates for each controlpoint in the X Map and Y Mapfields.

An error in map units isdisplayed at each controlpoint. An RMS error isdisplayed in map units and indigitizer inches.

6. Click OK to register the mapand close the Editing Optionsdialog box.

See Also

For information on configuringpuck buttons and establishingcontrol points, see �Setting up yourdigitizing tablet and preparingyour paper map� in this chapter.

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Tip

Missing Digitizer tabIf you installed ArcInfo beforeinstalling your digitizer, theDigitizer tab may be missing fromthe Editing Options dialog box. Toadd the tab, you must register thedigitizer.dll file. Go to the DOSprompt, type �cd� followed by thepath to the directory where youinstalled ArcInfo(%ARCHOME%\bin), and type�regsvr32 digitizer.dll�. When yourestart ArcMap, the EditingOptions dialog box will have theDigitizer tab.

ground coordinates are stored intic text files.

After you�ve entered the groundcoordinates, ArcMap displays anerror at each control point as wellas an RMS error. If the RMSerror is too high�greater than0.004 digitizer inches for highlyaccurate data or greater than0.008 digitizer inches for lessaccurate data�you can registerthe appropriate control pointsagain. For more information onerrors, see �Setting up yourdigitizing tablet and preparingyour paper map� in this chapter.

Saving new groundcoordinates

1. Follow steps 1 through 5 forregistering your map for thefirst time.

2. Click Save.

3. Navigate to the directory inwhich you want to save thecoordinates and type afilename.

4. Click Save.

5. Click OK.

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3

4

Registering your mapusing existing tic files orsaved coordinates

1. After adding a layer to yourmap, click the Editor menuand click Start Editing.

2. Click the Editor menu andclick Options.


4. Click Load.

5. Navigate to the file you wantto use.

6. Click Open. u

Tip

Removing recordsIf you want to remove all theground coordinate records andstart over, click Clear on theDigitizer tab. To remove anindividual record, click the numberin the Point column correspondingto the coordinates you want toremove and press the Delete key.

6

5Tip

Digitizer locationThe Digitizer tab also displays thecurrent x,y location of the digitizerpuck on the tablet. The coordinateschange as you move the puckalong the tablet surface. This helpsorient you to the location you�redigitizing.

Tip

Adding recordsIf you want to add additionalcontrol points after entering a few,click below the last record with themouse and digitize the new pointswith the digitizer puck.

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The ground coordinatesappear under the X Map andY Map fields.

7. Click the first record anddigitize the first control pointwith the digitizer puck.

8. Digitize each of the othercontrol points.

The digitized coordinatesappear in the X Digitizer andY Digitizer columns. An erroris displayed for each controlpoint, and an RMS error isdisplayed in map units and indigitizer inches.

9. Click OK to register the map.

Tip

Digitizing accuracyAlways register your map at thestart of each digitizing session,even if this means registering thesame map more than once. Yourpaper map might shift betweensessions; reregistering helpsensure that your digitizing isaccurate.

The ground coordinates are displayed.

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The digitized coordinates are displayed.

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Creating features using a digitizer

It�s easy to digitize features in ArcMap. You can digitize featuresinto a new map layer or edit an existing layer.

Digitizing modes

Digitizing tablets generally operate in two modes: digitizing(absolute) mode and mouse (relative) mode.

In digitizing mode, the location of the tablet is mapped to aspecific location on the screen. In other words, moving thedigitizer puck on the tablet surface causes the screen pointer tomove to precisely the same position. When you are in digitizingmode, you can only digitize features; you can�t choose buttons,menu commands, or tools from the ArcMap user interfacebecause the screen pointer is locked to the drawing area.

In mouse mode, the digitizer puck behaves just like a mouse;there is no correlation between the position of the screen pointerand the surface of the digitizing tablet, but you can chooseinterface elements with the pointer.

ArcMap lets you switch between digitizing and mouse modesusing the Editing Options dialog box. This means you can use thedigitizer puck to both digitize features and access user interfacechoices (as a substitute to the mouse) as you digitize.

Whether your digitizer is in mouse mode or digitizing mode, youcan still use your mouse at any time to choose interface elements.

Two ways to digitize features on a paper map

You can digitize features on a paper map in two ways: using pointmode digitizing or stream mode digitizing (streaming). You canswitch back and forth between the two modes as you digitize bypressing F8.

Digitizing by point

When you start a digitizing session, the default is point mode.With point mode digitizing, you convert a feature on a paper mapby digitizing a series of precise points, or vertices. ArcMap thenconnects the vertices to create a digital feature. You would usepoint mode when precise digitizing is required�for example,when digitizing a perfectly straight line.

Digitizing using stream mode

Stream mode digitizing (streaming) provides a quick and easyway to capture features on a paper map when you don�t require asmuch precision�for example, to digitize rivers, streams, andcontour lines. With stream mode, you create the first vertex of thefeature and trace over the rest of the feature with the digitizerpuck. When you�re finished tracing, you use the puck to completethe feature.

As you stream, ArcMap automatically adds vertices at an intervalyou specify; this interval, expressed in current map units, iscalled the stream tolerance. You can change the stream toleranceat any time, even while you�re in the process of digitizing afeature.

You can also digitize using stream mode when you create features�freehand� with the sketch construction tools. You can digitize instream mode with the Sketch tool, for example, in the same wayyou do from a paper map. The only difference is that you use themouse pointer to digitize freehand.

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Digitizingfeatures in pointmodePoint mode digitizing works thesame way with a digitizer as with�freehand� digitizing with theSketch tool; the only differenceis that with the digitizer you�reconverting a feature from a papermap using a digitizer puckinstead of a mouse.

Point mode digitizing involvesconverting point, line, andpolygon features from a papermap by digitizing a series ofprecise points, or vertices. Youdigitize each vertex by pressingthe puck button you configuredto perform a left mouse click. Tofinish the feature, press the puckbutton you configured to performa left double-click. ArcMapconnects the vertices to create adigital feature.

Before you begin digitizing, youmust set the digitizer to work indigitizing mode, rather than inmouse mode; this constrains thescreen pointer to the digitizingarea. When the puck is in u



3. Check Enabled to use thepuck in digitizing mode.

4. Click OK. u

See Also

For information on configuringpuck buttons and establishingcontrol points, see �Setting up yourdigitizing tablet and preparingyour paper map� in this chapter.

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See Also

For information on creatingfeatures by digitizing freehand withthe sketch creation tools, seeChapter 4, �Creating new fea-tures�.


6. With the digitizer puck,digitize the first vertex of thefeature.

7. Trace the puck over thefeature on the paper map,creating as many vertices asyou need.

8. Finish the feature by pressingthe appropriate puck button.

The feature is created.

Tip

SnappingTo help you digitize features in aprecise location on an existinglayer, you can use the snappingenvironment. For information onsnapping, see Chapter 4, �Creatingnew features�.

digitizing mode, you must useyour mouse to choose items inthe ArcMap interface�unlessyou have used VBA, or anotherdevelopment programminglanguage, to configure additionalpuck buttons to run specificArcMap commands.

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See Also

For information on configuringpuck buttons with programmingcode, see �Setting up yourdigitizing tablet and preparingyour paper map� in this chapter.

Tip

Deleting verticesClick the Undo button on theArcMap Standard toolbar to deletea vertex as you digitize.

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Digitizingfeatures instream modeWhen you digitize line orpolygon features from a papermap in stream mode (streaming),you create the first vertex of thefeature by pressing the digitizerpuck button you configured toperform a left mouse click. Youthen trace over the rest of thefeature with the digitizer puck.When you�re finished tracing,press the puck button youconfigured to perform a leftdouble-click to complete thefeature.

Before starting to digitize instream mode, you must set thestream tolerance�the interval atwhich ArcMap adds verticesalong the feature you�re digitiz-ing. Because the default streamtolerance is 0, you must enter atolerance value before you startdigitizing or the vertices will jointogether or overlap each other.You can change the streamtolerance any time in thedigitizing process.

You must also specify thenumber of streaming vertices youwant to group together. Thenumber you set tells ArcMaphow many vertices to deletewhen you click the Undo button.For example, if you set this u

Setting the streamtolerance

1. Click the Editor menu andclick Start Editing.



4. Type the stream tolerance (inmap units) in the Streamtolerance text box.

5. Click OK.

Setting the number ofvertices to be grouped



3. Type the number of verticesyou want to group together.

4. Click OK.

Now when you click the Undobutton while digitizing instream mode, the number ofvertices you specified aredeleted.

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Digitizing a feature instream mode


2. Follow steps 3 and 4 forsetting the stream tolerance.

3. Follow step 3 for setting thenumber of vertices to begrouped.


5. Check Enabled to use thepuck in digitizing mode.

6. Click OK.

7. Click the tool palettedropdown arrow and clickthe Sketch tool. u

Tip

SnappingTo help you digitize features in aprecise location on an existinglayer, you can use the snappingenvironment. For information onsnapping, see Chapter 4, �Creatingnew features�.

number to 20 and click the Undobutton while you�re digitizing afeature, ArcMap deletes the last20 digitized vertices from yourfeature.

To begin digitizing in streammode, you must choose Stream-ing from the Sketch tool contextmenu. You can switch back topoint mode at any time bypressing F8; press F8 again toswitch to stream mode again.

Before streaming, remember toset the digitizer to work indigitizing mode rather than inmouse mode; this constrains thescreen pointer to the digitizingarea.

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8. With the mouse pointer, right-click anywhere on the mapand click Streaming.

9. With the digitizer puck,digitize the first vertex of theline or polygon feature.

10.Trace the puck over thefeature on the paper map.

ArcMap creates vertices atthe stream tolerance youspecified.

11. Finish the feature by pressingthe appropriate puck button.


Tip

Choosing interfaceelements while streamingWhen you�re in the process ofdigitizing a feature in stream modeand want to interact with theArcMap interface using yourmouse�for example, to change thestream tolerance or undo anaction�you must first switch backto point mode by pressing F8. Afteryou have finished interacting withthe interface, you can resumestreaming by pressing F8 again.

Tip

Configuring a puck buttonfor streamingInstead of choosing Streamingfrom the context menu, you canconfigure one of your puck buttonsusing any development program-ming language, such as C++ orVBA, to activate stream modedigitizing. To learn more aboutconfiguring your puck buttons andcustomization in general, seeExploring ArcObjects.

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IN THIS CHAPTER

123

Creating features from other features 6• Copying a line at a specific

interval

• Creating a buffer around a feature

• Creating a mirror image of afeature

• Merging features from the samelayer into one feature

• Combining features from differentlayers into one feature

• Creating a feature from featureswith common areas

In spatial data editing, many new features can be created using the shapes ofother features. ArcMap has many tools you can use to create new featuresbased on features already in your database.

For example, you can construct a line that is a parallel copy of an existingline to create a centerline on a street. You can create a buffer around apoint, line, or polygon feature to show a specific area, such as a floodplainaround a river. You can also create a new feature by combining orintersecting existing features or even create a mirror image of a feature orset of features.

In this chapter, you�ll learn how easy it is to perform these tasks usingvarious tools in ArcMap.

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2. Click the line you want tocopy.

3. Click the Target layerdropdown arrow and clickthe layer to which you wantthe new line to belong. u

Copying a line ata specific intervalThe Copy Parallel commandcopies a line parallel to anexisting feature at a distance youspecify. If you give a distancethat is positive, the line is copiedto the right side of the originalfeature. A negative distance valuecopies the line to the left.

You might use the Copy Parallelcommand to create a streetcenterline or to create a gas linethat runs parallel to a road.

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CREATING FEATURES FROM OTHER FEATURES 125

The line is copiedparallel and tothe left of theoriginal feature ata distance of150 map units.

4. Click Editor and click CopyParallel.

5. Type the distance (in mapunits) from the originalfeature where you want tocopy the line and press Enter.

A parallel copy of the line iscreated at the specifieddistance.

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2. Click the feature or featuresaround which you want tocreate a buffer.

3. Click the Target layerdropdown arrow and click thelayer with the type of featuresyou want the buffer to be.(This can only be a line orpolygon layer.) u

Creating a bufferaround a featureYou can create a buffer around afeature using the Buffer com-mand. For instance, you mightuse Buffer to show the areaaround a well that�s contaminatedor to represent a floodplainaround a river.

You can buffer more than onefeature at a time, but a separatebuffer will be created aroundeach feature.

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A buffer of1,000 map units iscreated around thepoint.

4. Click Editor and click Buffer.

5. Type the distance (in mapunits) from the feature aroundwhich you want to create thebuffer and press Enter.

A buffer is created at thespecified distance.

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Creating a mirrorimage of afeatureThe Mirror task creates a mirrorimage of selected features on theother side of a line you create.You might use the Mirror task tocreate houses in a housingdevelopment where houses aremirror images of the ones on theopposite side of the street.

Also, as shown in the example,the Mirror task provides an easyway to add gas services to parcelsthat mirror the services on theother side of the street.


2. Click the feature or featuresthat you want to mirror.

3. Click the Current Taskdropdown arrow and clickMirror Features.


5. Construct a line by clickingonce on the startpoint andonce on the endpoint. u

Tip

Other ways to construct alineYou can also use the Distance�Distance and Intersection tools tocreate the endpoints of the line.For more information, see�Creating point features andvertices� in Chapter 4.

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New featuresAfter you digitize the end-point, a mirror image of thefeature or features is created.

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Merging featuresfrom the samelayer into onefeatureThe Merge command combinesfeatures from the same layer intoone feature. The features must bepart of a line or polygon layer.You could use the Mergecommand to combine two parcelsinto one.

You might also want to mergenonadjacent features to create amultipart feature. For example,you could merge the individualislands that make up Hawaii tocreate a multipart polygonfeature.

When you merge features in ageodatabase, the originalfeatures are removed and thenew feature�s attributes arecopied from the feature that wasselected first. If you mergecoverage or shapefile features,the attributes of the featurewith the lowest ID number (theoldest feature) are used.


2. Click the features that youwant to merge.

(The features must be fromthe same layer, either a lineor polygon layer.)

3. Click the Target layerdropdown arrow and click thelayer to which you want thenew feature to belong. u 2

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Parcels are merged into one.

4. Click Editor and click Merge.

The selected features aremerged into one.

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Combiningfeatures fromdifferent layersinto one featureThe Union command lets youcombine features from differentlayers into one feature whilemaintaining the original featuresand attributes. You might use thiscommand to create a salesterritory from several ZIP Codes.

You can also create a multipartfeature using the Union com-mand by combining nonadjacentfeatures from different layers.For example, suppose you wantto create a sedimentary rockpolygon in a new rock classifica-tion layer given selected clay andquartz polygons in an existingrock composite layer. You woulduse the Union command tocombine the clay and quartzfeatures to create a new, multi-part sedimentary rock feature inthe rock classification layer.

When you use the Unioncommand, the features youcombine must be from layers ofthe same type�line or polygon.The new feature is created in thecurrent layer with no attributevalues.


2. Click the features that youwant to combine into one.

(The features may be fromdifferent layers, although theymust be the same layertype—line or polygon.)

3. Click the Target layerdropdown arrow and click thelayer to which you want thenew feature to belong. u

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ZIP Codes are combined into one sales territory.

4. Click Editor and click Union.

The selected features arecombined into one.

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Creating afeature fromfeatures withcommon areasThe Intersect command createsa new feature from the areawhere features overlap. Forinstance, you might create anew sales territory out ofoverlapping trade areas.

You can find the intersectionbetween features of differentlayers, but the layers must be ofthe same type�line or polygon.The original features are main-tained, and the new feature iscreated in the current layer withno attribute values. You mustenter attribute values for the newfeature yourself.


2. Click the features from whoseintersection you want tocreate a new feature.

(The features may be fromdifferent layers, although theymust be the same layertype—line or polygon.)

3. Click the Target layerdropdown arrow and click thelayer to which you want thenew feature to belong.

(The layer must be of thesame type as the selectedfeatures—line or polygon.) u

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A single sales territory is createdfrom the areas in commonbetween two other sales territories.

4. Click Editor and click Inter-sect.

A new feature is created fromthe areas in common be-tween all selected features.

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ch6.p65 01/10/2001, 11:04 AM136

IN THIS CHAPTER

137

Editing existing features 7• Splitting a line or polygon

• Trimming a line

• Extending a line

• Flipping a line

• Placing points along a line

• Reshaping a line or polygon

• Adding and deleting sketchvertices

• Moving a vertex in a sketch

• Changing the properties of asketch

• Scaling features

• Clipping features

• Stretching geometry proportion-ately

This chapter shows you how to modify features that already exist in yourdatabase. Suppose you need to change the shape of a parcel toaccommodate a newly added cul-de-sac�you can use the Reshape Featuretask to modify the parcel to the proper shape. Suppose the street you�vedigitized doesn�t intersect with the correct cross street�you can use theExtend task to extend the line to the correct location. If you need to divide aparcel, you can use the Cut Polygon Feature task to cut the feature into two.

These are just a few examples of how easy it is to modify features whileediting in ArcMap. The editing tools, commands, and tasks provide a varietyof ways to make changes to existing features.

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Splitting a line orpolygonUsing the editing tools, you caneasily split line and polygonfeatures.

To manually split one line intotwo, use the Split tool. The line issplit at the location where youclicked with the mouse. Theattributes of the original line arecopied to each of the new lines.In the example shown, the Splittool is used to divide a streetcenterline into two features inanticipation of a new centerlinebeing added between the parcels.

You can also split a line into twousing the Split command on theEditor menu. Use the Splitcommand when you know thedistance at which you want tosplit the line, measured fromeither the first or last vertex. Youcan also use this command whenyou want to split a line at acertain percentage of the originallength. You might use the Split u

Splitting a line manually


2. Click the line you want tosplit.

3. Click the Split tool.

4. Click the spot on the linewhere you want it to split.

The line is split into twofeatures.

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Using snapping to split alineIf you want to use the Split tool tosplit a line at a specific vertex, usethe snapping environment to snapthe pointer precisely to the vertex.For more information on snap-ping, see Chapter 4, �Creating newfeatures�.

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EDITING EXISTING FEATURES 139

Splitting a line at aspecified distance orpercentage


2. Click the line you want tosplit.

3. Click Editor and click Split. u

command to split a power line ata known distance along the linewhen you want to add anelectrical pole that requires itsown service.

The Split dialog box displays thelength of the original feature incurrent map units to help yousplit it accurately. When you splitthe line using the Split command,the attributes of the original lineare copied to each of the newlines.

To split one polygon into two,use the Cut Polygon Featurestask. The polygon is splitaccording to a line sketch youcreate. The attributes of theoriginal feature are copied toeach of the new features.

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4. Click the first Split option tosplit the feature at a certaindistance.

Click the second Split optionto split the feature at a certainpercentage of the whole.

5. Type a distance or percent-age, as desired.

6. Click Forward if you want tosplit the feature starting fromthe first vertex.

Click Reverse if you want tosplit the feature starting fromthe last vertex.

7. Click OK.

The line is split into twofeatures according to theparameters you specified.

The line is split into twoaccording to the distance andorientation you specified.

Tip

Controlling how attributesare handledIf you�re working withgeodatabase features, you can setup split policies that control thebehavior of an object�s attributeswhen it is split. For more informa-tion on split policies, see Buildinga Geodatabase.

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Splitting a polygon


2. Click the polygon you want tosplit.

3. Click the Current Taskdropdown arrow and click CutPolygon Features.


5. Construct a line or polygonsketch that cuts the originalpolygon as desired.

6. Right-click anywhere on themap and click Finish Sketch.

The polygon is split into twofeatures.

Tip

Other ways to construct asketchYou can also use the Distance�Distance tool, the Arc tool, or theIntersection tool to create asketch. For more information, seeChapter 4, �Creating newfeatures�.

Tip

Cutting a polygon shapeout of a polygonYou can use the Cut PolygonFeatures task to create a sketchthat acts like a �cookie cutter�,splitting the polygon in two.Simply create a line sketch thatcloses in on itself by double-clicking precisely on the firstvertex of the sketch to finish it.

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The sketch “cuts” thepolygon into two features.

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Trimming a lineThe Trim command on theSketch context menu reducesthe length of a line, trimming adistance you specify from thelast vertex.

The Trim task in the CurrentTask dropdown list also trimslines, but instead of trimmingthem a given distance, the Trimtask uses a sketch you draw. u

Trimming a specificlength from the last point

1. Click the Current Taskdropdown arrow and clickModify Feature.


3. Click the line that you want totrim.

The line appears as a sketchwith vertices.

4. Right-click over any part ofthe line and click Trim.

5. Type the length you want totrim from the line (beginningat the last vertex marked inred) and press Enter.

The line is trimmed.

6. When finished modifying theline, right-click over any partof the sketch and click FinishSketch.

20 map units are trimmed from the original line.

Tip

Shortcut for modifyingfeaturesInstead of using the ModifyFeature task to change a feature toits sketch, you can click the Edittool and double-click the featureyou want to modify.

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Shortcuts for finishing asketchWhen you�re finished modifying asketch, you can press F2 to finishit. Simply selecting another featurewith the Edit tool will also finishthe sketch.

Tip

Trimming from the firstvertex of a lineYou can trim a line from the firstvertex instead of the last. See�Flipping a line� in this chapter.

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Trimming based on a lineyou draw

1. Click the Current Taskdropdown arrow and clickExtend/Trim Features.


3. Click the line or lines youwant to trim.


5. Construct a line that trims theselected line or lines asdesired.

6. Right-click anywhere on themap and click FinishSketch. u

3

This is useful if you don�t knowthe exact distance you want totrim but have a physical bound-ary where the features should endor begin.

Suppose your database has someroads that should end at thecoastline, but overshoot itinstead. Using the Trim task,you can draw a line sketch ontop of the coastline and thelines will be trimmed where youhave drawn the sketch.

Portions of the lines that are onthe right side of the sketch aretrimmed. The right side of thesketch is based on the directionin which the sketch was drawn.Imagine riding a bicycle alongthe sketch in the direction u

Tip

Shortcuts for finishing asketchYou can double-click on the lastvertex of a sketch to finish it. Youcan also press F2.

Tip

Other ways to construct asketchYou can also use the Distance�Distance tool, the Arc tool, or theIntersection tool to create a sketch.For more information, seeChapter 4, �Creating new fea-tures�.

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The lines are trimmed where the sketch was drawn.

in which the vertices wereadded. If you looked to yourright, you would be looking atthe right side of the sketch.

The lines are trimmed on theright side of the line youconstructed.

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Extending a lineThe Extend task is the oppositeof the Trim task, extendingselected lines to a line youconstruct. Consider the roads andcoastline example shown in theTrim task. If your database hassome roads that should end at thecoastline, but instead stop short,you could use the Extend task.By drawing a sketch on top ofthe coastline, you can extend theroads to the sketch you drew.

1. Click the Current Taskdropdown arrow and clickExtend/Trim Features.


3. Click the line or lines youwant to extend.


5. Construct a line to which youwant to extend the selectedline or lines.

6. Right-click anywhere on themap and click FinishSketch. u 3Tip


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The lines are extended to where the sketch was drawn.

The lines are extended to theline you constructed.

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3. Click the line whose direc-tion you want to change.

4. Right-click over any part ofthe sketch and click Flip.

The sketch becomes inverted(the first vertex becomes thelast, marked in red).


Flipping a lineWhen you modify a line bytrimming or extending it, the lineis automatically trimmed orextended from its last vertex.

However, if you prefer to trim orextend a line from the first vertexinstead of the last, you can usethe Flip command. The Flipcommand reverses the directionof a line so that the last vertex ofthe sketch becomes the first.

The first and last vertices of the line are reversed.

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2. Click the line you want todivide.

3. Click the Target layerdropdown arrow and click thepoint layer containing thetype of points you want toplace along the line.

4. Click Editor and clickDivide. u

Placing pointsalong a lineThe Divide command createspoints at a given interval alonga line. For instance, you coulduse Divide to place utility polesalong a primary.

You can create a specificnumber of points that areevenly spaced, or you cancreate points at a distanceinterval you choose.

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5. Click the first option and typea number to place a specificnumber of points evenlyalong the line.

Or click the second optionand type a number to placethe points at a specificinterval in map units.

6. Click OK.

The line is divided by pointsplaced along the line asspecified.

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Reshaping a lineor polygonThe Reshape Feature task letsyou reshape a line or polygonby constructing a sketch overthe feature. The feature takesthe shape of the sketch from thefirst place the sketch intersectsthe feature to the last.

When you reshape a polygon,if both endpoints of the sketchare within the polygon, theshape is added to the feature. u

1. Click the Current Taskdropdown arrow and clickReshape Feature.


3. Click the feature you want toreshape.


5. Create a line according to theway you want the featurereshaped.

6. Right-click anywhere on themap and click FinishSketch. u

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The feature is reshaped according to the sketch you constructed.

If the endpoints are outside thepolygon, the feature is cutaway.

When you reshape a line, bothendpoints of the sketch must beon the same side of the line.The line takes the shape of thesketch you draw.

The feature is reshaped.

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Adding a vertex to asketch


2. Click the Edit tool and clickthe line or polygon to whichyou want to add a vertex.

3. Move the pointer to whereyou want the vertex insertedand right-click.

4. Click Insert Vertex.

A vertex is added to thesketch.


Adding anddeleting sketchverticesYou can easily add vertices to ordelete vertices from a sketchusing the Insert Vertex andDelete Vertex commands on theSketch context menu. By addingor deleting vertices, you canreshape a feature when youobtain new or better geographicdata.

Suppose you have an existinglayer with curb lines and receivean aerial photo that shows thatthe lines in the layer are incor-rectly shaped. Using the aerial u

Tip

Adding vertices from thelast vertexYou can add vertices to a featurebeginning from the last vertex ofthe sketch. Click the Edit tool anddouble-click the feature to see itssketch. Then, click the Sketch toolto begin digitizing vertices.

A new vertexis added tothe sketch.

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Deleting a vertex from asketch



3. Click the line or polygon fromwhich you want to delete avertex.

4. Position the pointer over thevertex you want to deleteuntil the pointer changes.

5. Right-click and click DeleteVertex.

The vertex is deleted fromthe sketch.

6. Right-click over any part ofthe sketch and click FinishSketch.


The vertex is deleted, and the feature is reshaped.

photo as a backdrop, you can addvertices to the curb lines asneeded and then reshape thefeature to match the photo bymoving the vertices to newlocations. You can also reshapethe curb line features by deletingexisting vertices from theirsketches.

See Also

To learn how to move a vertex, see�Moving a vertex in a sketch� inthis chapter.

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Dragging a vertex


2. Click the Edit tool and clickthe line or polygon whosevertex you want to move.

3. Position the pointer over thevertex you want to move untilthe pointer changes.

4. Click and drag the vertex tothe desired location.



The vertex is moved, and the feature is reshaped.

Moving a vertexin a sketchMoving a vertex in a sketchoffers another way to modify orreshape a feature.

ArcMap lets you move a vertexin several ways: by dragging it,by specifying new x,y coordi-nates, or by moving it relative toits current location.

You might choose to drag avertex to a new location whenyou want to reshape a featureaccording to additional data youreceive. For instance, you candrag a vertex to reshape a roadfeature in an existing layer inorder to match it to the feature ina more accurate aerial photo.

You might move a vertex byspecifying new x,y locationswhen you obtain additional datathat provides the exact coordinatelocation at which the vertexshould be. For example, supposea parcel is resurveyed and a newGPS point is obtained for theparcel corner. You can move thecorner of the parcel to match thelocation found by the GPS byspecifying the equivalentlocation in x,y coordinates.

The Sketch context menu alsoprovides a way to move a u

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Moving a vertex byspecifying x,ycoordinates




4. Right-click and click Move To.

5. Type the x,y coordinateswhere you want to move thevertex.

The vertex is moved. u

vertex relative to its currentlocation. Suppose an electricalpole must be moved 15 feet eastand 5 feet north of its currentlocation due to a road widening.Before moving the pole, youmust reshape its electrical line sothat the pole can connect to theline in the new location; you cando this by moving the vertex ofthe electrical line on which thepole sits using relative (delta)x,y coordinates.

The original location of thevertex as the origin (0,0) is used,and the vertex is moved to thenew location using the map unitcoordinates you specify (15,5 inthis example). After the vertex ismoved and the electrical line isreshaped, you can snap the polefeature to the vertex in its newlocation.

Tip

Maintaining a feature’sshape when moving avertexYou can also move a vertex withoutchanging the shape of the feature.For more information, see�Stretching a feature�s geometryproportionately� in this chapter.

The vertex is moved accordingto the coordinates you specified.

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Tip

Undoing a vertex moveIf you move a vertex and don�twant it to stay in the new location,click the Undo button on theArcMap Standard toolbar. Thevertex returns to its last position.Click the Redo button if you wantto move the vertex back to the newlocation.

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Moving a vertex relativeto its current location




4. Right-click and click Move.

5. Type the delta x,y coordi-nates where you want tomove the vertex. u

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The vertex is moved.




The vertex is movedaccording to thecoordinates youspecified.

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Changing theproperties of asketchWhen creating a new feature ormodifying an existing one, youcan easily change the propertiesof the sketch shape using theSketch Properties dialog box.

Using the Sketch Propertiesdialog, you can remove partsfrom a multipart feature, insertand delete vertices, and alter them- and z-values of vertices.

Suppose you are editing a layerthat contains river features whoseshapes contain too many vertices.You could use the SketchProperties dialog box to selectunwanted vertices and deletethem.

Deleting multiple verticesfrom a feature

1. Click the Edit tool and selectthe feature whose shape youwant to modify.

2. Click the Current Taskdropdown arrow and clickModify Feature to place theshape of the feature in theedit sketch.

3. Right-click the sketch andclick Properties.

4. Select the vertices that youwant to remove by holdingdown the Shift key andclicking vertices from thetable. Use the Shift and Ctrlkeys to select more than onevertex.

5. Click the Delete key or right-click over the selectedvertices and click Delete.

The vertices form the sketch.

6. Click Finish Sketch.

Tip

How do I know whichvertices I have selected?As you select vertices in the dialogbox, they turn orange on the map.

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Inserting a vertex at themidpoint of a segment

1. Right-click over a segment ofthe edit sketch and clickProperties.

2. Select the vertex beforewhich you wish to insert anew vertex.

3. Right-click the selected vertexand click Insert Before.

Tip

Modifying thex,y coordinatesIf you don�t want the added point tobe exactly at the midpoint betweentwo vertices, click the x or y columnand type in a new coordinate forthe point.

Vertex inserted at midpoint

Tip

Insert vertices after aselected vertexYou can insert vertices eitherbefore or after the vertex that youright-click on top of.

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Removing a part from amultipart feature

1. Click the Edit tool and selectthe feature you want toremove a part from.

2. Click the Current Taskdropdown arrow and clickModify Feature to place themultipart shape in the editsketch.

3. Right-click the sketch andclick Properties.

4. Right-click the part that youwant to remove and press thedelete key or right-click andclick Delete.


Tip

How do I know which partsI have selected?When you select a part from theSketch Properties dialog box, thesegments for that part will appearthicker.

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Editing z- and m-valuesof a feature

1. Click the Edit tool and selectthe feature whose z- or m-values you wish to edit.


3. Right-click on top of thesketch and click Properties.

4. Select the vertex you wish tomodify.

5. Click the z or m field in thetable and type a new value.


Tip

Using the Current Z controlWhen you add points to the editsketch, you can control the z-valuefor each vertex using the Current Ztool.

To use the Current Z tool, you mustfirst add it to a toolbar from theCommands tab of the Customizedialog box. The Current Z tool islisted in the Editor category.

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Scaling featuresYou can scale a feature�makethe entire feature larger orsmaller�using the Scale tool.The feature is scaled based on thelocation of the selection an-chor�the small �x� located inthe center of selected features.

You might use the Scale toolwhen working with data from anew source in which the scale isslightly inaccurate�for example,subdivision parcels from asurveyor. You can use the Scaletool to scale parcels so that theyfit together properly.

To use the Scale tool, you mustfirst add it to a toolbar from theCommands tab of the Customizedialog box. The Scale tool isavailable from the Editorcategory. For more informationon adding a tool to a toolbar, seeExploring ArcObjects.


2. Click the feature you want toscale.

3. Click the Scale tool.

4. Move the selection anchor ifnecessary.

5. Click and drag the pointerover the feature to scale it asdesired. u

Tip

Moving the selectionanchorTo move the selection anchor of afeature you want to scale, hold thescaling pointer over the anchoruntil the icon changes. Then, clickand drag the anchor to a newlocation.

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Tip

Scaling more than onefeatureYou can scale more than onefeature at the same time. Simplyselect all the desired features andmove the selection anchor to thedesired location before using theScale tool.

6. Release the mouse buttonwhen you’re finished scalingthe feature.

The feature is scaled.

Tip

Undoing scalingTo return a feature to its originalsize after scaling it, click the Undobutton on the ArcMap Standardtoolbar.

The feature is scaled.

Tip

Scale factorYou can scale features using ascale factor instead of draggingthe mouse. Click the F key to setthe scale factor.

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Clipping featuresYou can easily clip features thattouch or are within a buffereddistance of selected features.

Suppose that you want tomodel the effect of a proposedroad-widening project on thelots of a subdivision block. Youcan do this using the Clipcommand. Select the roadcenterline where the proposedwidening is to occur and thenclick Clip from the Editor menu.Type the length measurement ofthe widening and click theoption to Discard the area thatintersects to clip the subdivi-sion lots.

When using the Discard thearea that intersects option, theClip command will buffer theselected road feature and thenclip all portions of editablefeatures that are within thebuffered region. Using the�Preserve the area that inter-sects� option, all features thattouch the buffered feature willbe deleted.

1. Select the feature you wantto use to clip features.

2. Click Editor and click Clip.

3. Type a buffer value. You canleave the value as 0 if youare using a polygon featureto clip with.

4. Click the type of clip opera-tion you wish to use.

5. Click OK to clip the feature.

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Stretching geometry proportionately

Sometimes you want to stretch a feature without changing itsgeometry (shape). Suppose you want to change the position of afeature in relation to other features by moving a vertex. Forexample, perhaps the data you have for an electric transmissionsystem is not as accurate as you would like. However, you haveother layers containing accurate surveyed points that coincidewith some of the transmission towers, power generating plants,and substations. By moving the vertices of the transmission lines,you can adjust the positions of the lines to the known surveyedpositions of the features in the more accurate layer. You canchange the positions of these vertices without changing thegeneral shape of the transmission lines by stretching the featuresproportionately.

When you stretch a feature proportionately, the proportions of thefeature�s segments are maintained, thereby maintaining thegeneral shape of the feature. This is different from moving avertex to reshape a feature.

The graphics below show the difference between moving a vertexto reshape a feature and moving a vertex while maintaining theshape of the feature. The three graphics on the top show how afeature is modified when its upper-right vertex is moved withproportionate stretching turned on. The three graphics on thebottom show how the same feature is reshaped when its upper-right vertex is moved with proportionate stretching turned off.

Proportionate stretching on

Proportionate stretching off

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Stretching afeature’sgeometryproportionatelyWithin the Editing Optionsmenu, you can choose to stretchthe geometry of features propor-tionately when moving vertices.When you drag a vertex to a newlocation with this option turnedon, the proportions of thefeature�s segments are main-tained, thereby maintaining thegeneral shape of the feature.

You might want to stretchfeatures proportionately whenmerging data from different datasources�for example, utilitylines from one source andsubdivision parcels from another.

Suppose the data for the subdivi-sion parcels is very accurate, butthe data for the utility lines is notas accurate. While the shapes ofthe utility lines are generallycorrect, you want to change theposition of one line relative tothe parcels by moving a vertex.By stretching the utility linefeature proportionately, you canmake it fit accurately with theparcels without losing the generalshape of the line. u


2. Click the Edit tool and clickthe feature you want tostretch.



5. Check the check box tostretch the feature proportion-ately.

Uncheck the check box if youwant to reshape the featurewithout maintaining propor-tionate geometry.

6. Click OK. u

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You can turn on proportionatestretching by checking a box onthe General tab of the EditingOptions dialog box. Uncheck thebox if you simply want toreshape a feature withoutmaintaining proportionategeometry.


8. Drag the vertex to the desiredlocation.


The feature is stretchedproportionately.

See Also

To see how stretching a featureproportionately looks in compari-son to stretching a feature toreshape it, see �Stretchinggeometry proportionately� in thischapter.

7

The feature is stretchedproportionately.

8

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IN THIS CHAPTER

169

Editing topological features 8• Integrating topological data

• Moving a shared vertex orboundary

• Reshaping a shared boundary

• Modifying a shared boundary

• Creating a new polygon withshared parts

Most vector datasets�whether they are shapefiles, coverages, or featuredatasets�have features that share boundaries or corners. Editing a boundaryor vertex shared by two or more features updates the shape of each of thosefeatures. This is called a topological association.

A topological association means that some parts of the features� shapes sharethe same location. In addition, different feature classes in a feature datasetoften share geometry between them. For example, moving a slope boundaryin one feature class would also update a forest stand in another feature class.

The topology tools in ArcMap let you maintain topological associationsbetween features and between feature classes when you edit shapefiles,coverages, or feature datasets. In this chapter, you will learn how to use thetopology tools as well as how to create topologically integrated data.

Topological associations in a geometric network are not discussed here; theyare covered in Building a Geodatabase. For detailed information abouttopology in general, see Modeling Our World. Information specific to editingcoverage topology is covered in Appendix A, �Editing coverages in ArcMap�.

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Integrating topological data

Before you edit data that has topological associations, the datamust be topologically integrated so that all features with partsthat should be shared are shared.

Automatic integration

When you begin to edit topological data with the topology toolsin ArcMap, the tools will automatically integrate the area you areediting if that area has not already been integrated. This involveschecking all feature classes in your feature dataset and makingany boundaries or vertices within a certain distance rangeidentical, or coincident. This distance range is called the clustertolerance. The cluster tolerance determines the range withinwhich features are made coincident. When you edit data with thetopology tools, ArcMap always integrates the data at the smallestpossible cluster tolerance value.

Manually integrating data

You can also manually integrate shapefiles and geodatabasefeature datasets using the Integrate command. You mightmanually integrate data in this way if you want to specify acluster tolerance that is different from the one used toautomatically integrate the data.

For example, suppose you specify a cluster tolerance of 5 mapunits. Suppose your data had a parcel boundary that should beshared with the adjacent parcel boundary but was 4 map unitsaway. After running Integrate, the boundaries of the two parcelswould be made coincident because they were within the clustertolerance of 5 map units.

To minimize error, the cluster tolerance you choose should be assmall as possible, depending on the precision level of your data.For example, if your data is accurate within 10 meters, you wouldwant to set your cluster tolerance no larger than 10 meters andsmaller if possible. The default cluster tolerance is 0,representing the minimum possible tolerance value. This defaultvalue is applied if you don�t specify a cluster tolerance.

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EDITING TOPOLOGICAL FEATURES 171

1. Add the shapefile or featuredataset you want to integrateto your map.

2. Click the Editor menu andclick Start Editing.


4. Click the Topology tab.

5. Uncheck the check box only ifyou want to integrate theentire dataset.

Leave it checked if you wantto integrate features in thecurrent map extent.

6. Type the distance range (inmap units) within which youwant features to be coinci-dent.

7. Click OK. u

Integrating dataBefore you edit data withtopological associations, it mustbe topologically integrated.

As discussed in the previoussection, ArcMap automaticallyintegrates topological data that isnot already integrated when youbegin to edit it with the topologytools.

However, if you wish to manu-ally integrate shapefiles orfeature datasets in a geodatabase,you can use the Integrate u

Tip

When should I manuallyintegrate my data?Use the Integrate command whenyou want to integrate yourshapefile or geodatabase featuredataset using a cluster tolerancethat is different from the minimumtolerance ArcMap uses when itautomatically integrates your data.

See Also

For a description of the differenttypes of data you can edit inArcMap, see Chapter 3, �Editingbasics�.

See Also

For more information on choosinga cluster tolerance, see �Integratingtopological data� in this chapter.

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8. Click Editor and click Inte-grate.

The data is integrated.

Tip

“Undoing” an IntegrateYou can undo an Integrate byclicking the Undo button on theArcMap Standard toolbar.

command on the Editor menu.This involves setting a clustertolerance and specifying whetheryou want to integrate the entiredataset or only the features in thecurrent map extent.

The Integrate the visible extentonly check box�on the Topol-ogy tab of the Editing Optionsdialog box�is checked bydefault to integrate only thefeatures in the current mapextent. Uncheck the check boxonly if you want to integrate theentire dataset.

When you integrate a featuredataset, you are integrating all ofthe feature classes it contains,even the ones that are not visibleon the map. You should thereforemake sure that you know thecontents of your dataset beforeyou integrate it.

You cannot manually integratecoverages. When you use thetopology tools to edit a coveragethat is not already integrated, thecoverage is integrated automati-cally using the smallest possiblecluster tolerance.

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Moving a sharedvertex orboundaryUse the Shared Edit tool tomove parts of features that areshared. This tool also selectsparts of features on which youwant to use other topologytools. The Shared Edit tool isdesigned to select vertices orboundaries that are sharedbetween two or more features.

When you select with theShared Edit tool, only thetopmost visible vertex orboundary on the map ishighlighted. However, everyvertex or boundary in thedataset underneath where youclicked on the map is actuallyselected. This ensures thatwhen you move part of afeature that is shared, anycoincident vertices or bound-aries underneath will moveappropriately, as well as anyvertices or boundaries con-nected to those parts. This istrue even for feature classesthat aren�t visible on the map.

Moving a shared vertex


2. Click the shared vertex youwant to move.

The selected vertex ishighlighted.

3. Drag the vertex to the desiredlocation.

The location of the vertex isupdated, along with allcoincident vertices orboundaries in the dataset, aswell as any connectedvertices or boundaries.

The vertex, all coincident vertices and boundariesin the dataset, and any connected vertices andboundaries are moved.

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Moving a sharedboundary


2. Click the shared boundaryyou want to move.

The selected boundary ishighlighted.

3. Drag the boundary to thedesired location.

The location of the boundaryis updated, along with allcoincident vertices orboundaries in the dataset, aswell as any connectedvertices or boundaries.

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The boundary, allcoincident vertices andboundaries in the dataset,and any connected verticesand boundaries are moved.

Tip

“Undoing a shared edit”You can undo a shared edit byclicking the Undo button on theStandard toolbar. If the edithappened in an area that wasautomatically integrated, you needto click Undo twice to remove theautomatic integration.

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Reshaping ashared boundaryYou can use the Shared Edittool to select a shared bound-ary you want to reshape. TheReshape Feature task lets theboundary take the shape of asketch you draw from the firstintersection to the last. Thesketch must intersect theboundary at least twice.

When you reshape a sharedboundary, all coincident verticesand boundaries, as well as anyconnecting vertices or bound-aries, are reshaped as well.

1. Click the Current Taskdropdown arrow and clickReshape Feature.


3. Click the shared boundaryyou want to reshape. u

See Also

For more information on reshap-ing a feature using a sketch, see�Reshaping a line or polygon� inChapter 7.

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Tip

Other ways to construct asketchYou can also use the Distance�Distance tool, the Arc tool, or theIntersection tool to create asketch. For more information, seeChapter 4, �Creating newfeatures�.


5. Create a line according to theway you want the featurereshaped.

6. Double-click the last vertex tofinish the sketch.

The boundary and allcoincident vertices andboundaries, as well as anyconnecting vertices orboundaries, are reshaped.

The boundary, allcoincident vertices andboundaries, and anyconnecting verticesand boundaries arereshaped.

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Modifying ashared boundaryYou can use the Shared Edittool to select a shared bound-ary that you want to modify.Then, use the Modify Featuretask to see the sketch of theboundary.

You can modify the sketchboundary as you would anyfeature sketch�by inserting,deleting, and moving verticesusing the Sketch context menu.

When you modify the boundaryselected with the Shared Edittool, all coincident vertices andboundaries as well as anyconnecting vertices or boundariesare modified accordingly.



3. Click the shared boundaryyou want to modify.

The sketch of the boundaryappears. u

Tip

Shortcut for modifyingshared boundariesInstead of using the ModifyFeature task to change a sharedboundary, you can click the SharedEdit tool and double-click theshared boundary you want tomodify.

See Also

For more information on modify-ing features, see Chapter 7,�Editing existing features�.

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4. Modify the sketch as desired.

5. Right-click anywhere overthe boundary and click FinishSketch.

The boundary and allcoincident vertices andboundaries, as well as anyconnecting vertices orboundaries, are modifiedaccordingly.

The boundary, all coincident verticesand boundaries, and any connectingvertices and boundaries are modified.

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Creating a newpolygon withshared partsUse the Auto CompletePolygon task to create a newpolygon if it shares part of itsboundary with one or moreexisting polygons. This way, it�snot necessary to re-create theportion of the polygon that�salready represented.

When you create a newpolygon in this way, all bound-aries and vertices of thepolygon are automaticallyshared with the existingpolygons.

1. Click the Current Taskdropdown arrow and clickAuto Complete Polygon.

2. Click the Target layerdropdown arrow and click apolygon layer.

3. Click the Sketch tool.

4. Create a sketch that startsand stops at any of theexisting polygon boundariesto enclose the new polygonyou are creating.

You can overshoot theexisting boundaries whenyou create the line; they willbe trimmed automatically.

5. Double-click to finish thesketch. u

Tip

Using the snappingenvironment to create asketchYou can use the snapping environ-ment to help you snap to existingpolygon boundaries when creatinga sketch. For more information onsnapping, see Chapter 4, �Creatingnew features�.

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Secondvertex

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Firstvertex

Thirdvertex

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Any vertices or boundariesnecessary to complete thepolygon are created andautomatically shared. Anyovershoots from the sketchyou drew are removed.

All the vertices and boundaries of the polygonare created and automatically shared.Overshoots from the sketch are removed.

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IN THIS CHAPTER

181

9• Viewing attributes

• Adding and modifying attributes

• Copying and pasting attributes

Editing attributes

GIS database editing not only involves creating and editing features; it alsoinvolves assigning and updating the attributes, or characteristics, of features.

ArcMap makes it easy to view and update the attributes of features in yourdatabase. You can edit feature attributes in two ways: using the Attributesdialog box or using a feature layer�s attribute table. This chapter focuses onediting attributes using the Attributes dialog box. With the Attributes dialogbox, you can view the attributes of selected features on your map; add,delete, or modify an attribute for a single feature or multiple features at thesame time; and copy and paste individual attributes or all the attributes of afeature.

You can perform similar functions using a feature layer�s attribute table.However, with tables you can also do computations�such as adding andsorting records�with attribute values. To learn how to edit attributes in anattribute table�including performing computations with attribute values�see Using ArcMap.

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Viewing attributesThe Attributes dialog box letsyou view the attributes offeatures you�ve selected in yourmap. The left side of the dialogbox lists the features you�veselected. Features are listed bytheir primary display field andgrouped by layer name. Thenumber of features selected isdisplayed at the bottom of thedialog box.

The right side of the Attributesdialog box is called the propertyinspector. The property inspectorcontains two columns: theattribute properties of the layeryou�re viewing, such as Type orOwner, and the values of thoseattribute properties.


2. Select the features whoseattributes you want to view.

3. Click the Attributes button.

4. Click the layer name thatcontains the features whoseattributes you want to view.

The layer’s attribute proper-ties appear on the right sideof the dialog box. u

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Tip

Finding the feature on themapYou can find a selected feature onthe map by either highlighting orzooming to it. To highlight thefeature, click the primary field andthe feature will flash on the map.Right-click the field and clickZoom To in the context menu to geta close-up view of the feature.Click the Back button on the Toolstoolbar to return to the previousmap extent.

4

The layer’s attributeproperties appear.

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EDITING ATTRIBUTES 183

5. Double-click a layer name tosee the primary display fields,representing the selectedfeatures in the layer.

Double-click again to hidethe primary display fields.

6. Click a primary display fieldto see the correspondingfeature’s attribute values.

The corresponding featureflashes on the map.

7. Click the Close button toclose the dialog box.

Tip

Viewing attributes in theIdentify Results windowTo view the attributes of a featurequickly, click the Identify Featuresbutton on the Tools toolbar, thenclick the feature whose attributesyou want to view. View thefeature�s attributes in the IdentifyResults window.

Tip

Delete a selected featureIf you want to delete a featurewithout losing your selection,simply right-click on the featureand click Delete from the contextmenu.

Tip

Changing the primarydisplay fieldYou can change the primarydisplay field for a layer on theFields tab of the layer�s Propertiesdialog box. To open the dialogbox, right-click the layer name inthe table of contents.

Tip

Unselect a featureYou can remove features from theselection without having to clickon the map. To remove a featurefrom the selection, right-click onthe feature and click Unselect fromthe context menu.

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Adding andmodifyingattributesThe easiest way to make changesto the attributes of a selectedfeature is by using the Attributesdialog box.

You can add or modify attributesof selected features as needed.For example, you might want toupdate the attribute values�suchas its name and maintenanceinformation�for a park featureyou created.

To add or modify an attributevalue for a single feature, clickthe primary display field for thefeature on the left side of thedialog box and make yourchanges in the Value column onthe right. u

Adding an attribute valueto a single feature

1. Click the primary display fieldof the feature to which youwant to add an attributevalue.

2. Click in the Value columnwhere you want to add theattribute value.

3. Type the attribute value andpress Enter.

The attribute value is addedto the feature.

Adding an attribute valueto all selected features ina layer

1. Click the layer to which youwant to add an attributevalue.

2. Click in the Value columnwhere you want to add theattribute value.

3. Type the attribute value andpress Enter.

The attribute value is addedto all selected features in thelayer.

Tip

Attribute domainsYou can use attribute domains tocreate a list of valid values for afeature in a geodatabase. You canalso use the Validate command toensure attribute quality. For moreinformation, see Building aGeodatabase.

Tip

Saving your editsClick the Editor menu and clickSave Edits.

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Modifying an attributevalue for a feature

1. Click the primary display fieldof the feature for which youwant to modify an attributevalue.

2. Click the value you want tomodify.

3. Type a new attribute valueand press Enter.

The attribute is modified forthe feature.

Modifying an attributevalue for all selectedfeatures in a layer

1. Click the layer for which youwant to modify an attributevalue.

2. Click in the Value columnnext to the attribute propertyyou want to modify for allselected features in the layer.

3. Type a new attribute valueand press Enter.

The attribute is modified forall selected features in thelayer.

You can also add or modify anattribute value for all selectedfeatures in a layer at the sametime. Simply click the layer nameon the left and make yourchanges in the Value column onthe right.

Tip

Performing calculationsWhen editing attributes, you mightneed to perform calculations usingthe field calculator in the featurelayer�s attribute table dialog box.For more information, see UsingArcMap.

Tip

Adding attribute propertiesYou can add an attribute propertyfor a feature�for example, Owneror Type�by working with itsattribute table in ArcCatalog. Formore information, see UsingArcCatalog.

Tip

Deleting attributesTo delete an attribute value, right-click over the value and clickDelete. You can also press theDelete key to delete an attributevalue.

Tip

Undoing your editsTo undo any edit to featureattributes, click the Undo buttonon the ArcMap Standard toolbar.

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Copying andpasting attributesCopying and pasting is an easyway to edit the attributes offeatures on your map. You cancopy individual attribute valuesor all the attribute values of afeature. Attribute values can bepasted to a single feature or to allselected features in a layer.

Copying and pastingindividual attributevalues from feature tofeature

1. Click the attribute value youwant to copy.

2. Right-click the value you wantto copy and click Copy.

3. Click the primary display fieldof the feature to which youwant to paste the value.

4. Click where you want topaste the value.

5. Right-click where you want topaste the value and clickPaste.

The attribute value is pastedto the feature.

Tip

Copying and pastingindividual attribute valuesto an entire layerTo copy an attribute value to alayer, click the value you want tocopy, right-click, and click Copy.Then, click the layer name andright-click in the Value columnnext to the appropriate property.Click Paste and the attribute valueis copied to every selected featurein the layer.

Tip

Cutting and pastingattributesCutting and pasting attributes issimilar to copying and pastingthem. Right-click and click cutfrom the context menu to removethe attribute value from its currentlocation in the Attributes dialogbox, then click Paste to paste itelsewhere.

The attribute valueis pasted to the feature.

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Copying and pasting allattribute values fromfeature to feature

1. Right-click the primary displayfield of the feature whoseattribute values you want tocopy and click Copy.

2. Right-click the primary displayfield of the feature to whichyou want to paste theattribute values and clickPaste.

The attribute values arepasted to the feature.

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Attribute values arepasted to the feature.

Tip

Copying and pasting allattribute values from onefeature to an entire layerYou can copy all attribute valuesfrom one feature to all selectedfeatures in a layer. Right-click theprimary display field of the featurewhose attribute values you want tocopy and click Copy. Right-clickthe layer name to which you wantto paste the attribute values. ClickPaste and the attribute values arecopied to every selected feature inthe layer.

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ch9.p65 01/10/2001, 11:25 AM188

IN THIS APPENDIX

189

A• Coverages and topology

• Creating new coverage features

• Creating nodes

• Creating points and labels

• Creating polygons

• Creating regions and routes

• Editing coverage features

• Splitting and merging adjacentpolygons

• Deleting and moving polygons

• Splitting and merging arcs

• Deleting and moving arcs

• Merging regions and routes

ArcMap lets you edit ArcInfo coverages, ESRI shapefiles, personalgeodatabases, and multiuser geodatabases. It was designed to be easy to useand learn. As much as possible, ArcMap provides a normalized approach toediting all of these data sources. A key part of this design is that featuresfrom these data sources are presented to ArcMap as objects. When editingcoverage data, users familiar with ARCEDIT� should be aware that thereare several basic differences in the approach of these systems.

You will find that the basic patterns of editing geographic data are present inArcMap, and much of what you know about editing topology will help youlearn to edit coverages quickly. Please read Chapter 8, �Editing topologicalfeatures�, to learn more about topological editing.

This appendix describes the underlying coverage data model. It guides youthrough the process of creating coverage features and then outlines eachediting task that is unique to coverage features.

Editing coverages in ArcMap

AppendixA.p65 01/10/2001, 11:30 AM189


Coverages use a collection of feature classes to representgeographic features; each feature class stores a set of points,lines (arcs), polygons, or annotation (text). To define thegeographic features, more than one feature class is oftenrequired. For example, both line and polygon feature classes existin a coverage representing land use areas. Polygon features alsohave label points, which are stored in a separate feature class.

Feature classes can be separated into three distinct types:primary, secondary, and composite.

Primary feature classes include points (label points), lines (arcs),polygons, and nodes. When node and polygon feature classesare present in a coverage, the coverage has topology and thefeatures in those classes contain relationships, calledtopological associations, with other features: arcs form theperimeter of polygons, nodes are located at the endpoint of arcs,and label points mark the interiors of polygons.

These topological associations between features are storeddirectly in the feature class tables. For example, the topologicalassociation between a node feature and an arc feature is definedby the ARC#, FNODE#, and TNODE# items.

This type of association is often referred to as �Arc�nodetopology�.

Coverages and topology

Likewise, the topological association between an arc feature anda polygon feature is defined by the ARC#, LPOLY#, and RPOLY#items.

This type of association is often referred to as �Polygon�arctopology�.

In order to maintain topological associations between featureswhile editing in ArcMap, you must use the topology tools. Usingthe Shared Edit tool, you can reshape the boundary of a polygon,and the shape of the arc will be updated automatically, thusmaintaining the association between features. For moreinformation about using topology tools, see Chapter 8, �Editingtopological features�.

Secondary feature class types include tics, links, annotation, andsections. Tics are used for map registration, and links are used foradjusting features. Sections are the building blocks of ameasurement system that is stored on composite route features;annotation is text labels displayed on a map. Secondary featureclasses cannot be edited in ArcMap.

Coverages also contain composite feature classes calledsubclasses. Routes are collections of arcs with an associatedmeasurement system, while regions are collections of polygons,which can be adjacent, disjoint, or overlapping.

ARC# FNODE# TNODE#

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ARC# RPOLY#LPOLY#

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EDITING COVERAGES IN ARCMAP 191

Coverages and feature types

Feature classes Feature type

Points only, arcs only Simple

Points and arcs Simple

Arcs and nodes Topo

Polygons only Topo

Arcs and polygons Topo

Arcs, polygons, and region subclasses Topo

Arcs and route subclasses Topo

Arcs, polygons, region, and route subclasses Topo

ArcMap and coverage feature class types

ArcMap identifies all coverage features as either simple featuresor topo features.

Simple features do not contain topological associations withother features. For example, well locations stored in a single-pointfeature class coverage are simple features. Coverages thatcontain simple features do not store topology. All editing toolscan be used to create and update simple features.

Topo features store and maintain topological associations withother features in a coverage. For example, parcels stored in apolygon feature class maintain an association with line featuresstored in the arc feature class. You can attach attributes such assurvey measurements or line type to the line features and modelparcel ownership or tax value on the polygon features. Coveragesthat contain node and/or polygon features store topology.

ArcMap ensures that those topological associations aremaintained by disabling editing tools that could invalidate therelationship. For example, when you select a polygon featureusing the Edit tool, the Rotate command is disabled.

When you want to edit features that contain topologicalassociations with other features, you need to select theboundaries and points that are shared between features. You canselect and edit shared boundaries using the Shared Edit tool. Formore information about the Shared Edit tool and editingtopological features, see Chapter 8, �Editing topological features�.

The table below identifies feature types based on the number andtypes of feature classes that are present in a coverage.

The next topic guides you through the process of creating eachtype of coverage feature that can exist in a coverage. It explainshow topological associations are created and maintained for eachtopo feature that you create.

The topic that follows describes editing tasks that are specific totopo features. For example, suppose you want to merge twopolygons together. You need to select and delete the sharedboundary between them using the Shared Edit tool�if you selectboth polygons using the Edit tool, the Merge command will bedisabled. Editing tasks that are unique to coverage features aredescribed in detail.

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Creating newcoveragefeaturesThe steps for creating acoverage feature may differ,depending on the type ofcoverage feature you want tocreate.

To create primitive features(points, arcs, and polygons),use the Create new feature taskand digitize a shape using thesketch tools.

If the primitive feature is a topofeature, related features may becreated to support the con-struction. For example, if youcreate a new polygon feature,new arc features and a labelpoint feature will be createdautomatically.

To create composite features(routes and regions) you needto use the Union command.

Creating an arc feature


2. Click the Target layerdropdown arrow and click acoverage line layer.


4. Click the map to create anew line sketch.

5. Double-click to finish thesketch and create a newline feature.

If the arc coverage containsnode features, nodes will becreated at the endpoints ofthe line.

Digitizing an arc thatcrosses the boundary of apolygon that also belongs tothe same coverage will splitthe polygon in two.

Tip

Coverage tolerancesWhen creating new arc features,use snapping to ensure arc�nodeconnectivity. Coverage editingtolerances (NodeSnap, ArcSnap,Weed, and Snapping) do not workin ArcMap. See �Using thesnapping environment� inChapter 4.

Suppose you wantto create a new archere.

3

A new arc featureis created.

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AppendixA.p65 01/10/2001, 11:31 AM192



2. Click the Target layerdropdown arrow and click acoverage node layer.


4. Click an existing arc to add anew node feature.

Creating a nodeCoverage node featuresconnect arc features together.When you create a new arcfeature, node features areautomatically placed at theendpoints of the arc feature.However, you can use theCreate New Feature task to addnodes to your coverage. Whenyou create a new node featurethe node must touch orintersect an existing arc feature.

If you need to connect arcfeatures together but do nothave a node feature class inyour coverage, you must createone using ArcCatalog prior toediting. You create node featureclasses by generating arc�nodetopology. To learn more aboutcreating coverage topology, seeUsing ArcCatalog.

Tip

Use snapping whencreating node featuresYou can use snapping to ensurethat nodes snap to existing arcfeatures. For more informationabout snapping, see �Using thesnapping environment� inChapter 4.

Suppose you wantto create a new

node here.

1

2

3

A new node featureis created, and the

arcs are split.

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2. Click the Target layerdropdown list and click acoverage point or label layer.


4. Click to add the point feature.

Creating pointand labelfeaturesSimple point and label pointfeatures do not participate inthe topology of a coverage.However, label points are usedas placeholders for the at-tributes of polygons. You cancreate new points and labelpoints using the Create NewFeature task.

When you create a newcoverage polygon, a label pointis added automatically. You canadd multiple label points insideof a polygon. Multiple labelpoints can be used for ad-vanced label placement. Eachpoint will contain the sameattribute information as thepolygon feature and any otherlabel points inside of thatpolygon.

A new labelfeature is created.

3

1

2

Suppose you wantto create a new

label here.

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2. Click the Target layerdropdown arrow and click acoverage polygon layer.


4. Click the map to create anew polygon sketch.

5. Double-click to finish thesketch and create a newpolygon feature.

Tip

Using the Auto CompletePolygon taskIn addition to using the Create NewFeature task, you can use the AutoComplete Polygon task and digitizea line to create new features. Tolearn more about the AutoComplete Polygon task, see�Creating a new polygon withshared parts� in Chapter 8.

Creating polygonfeaturesYou can create new coveragepolygon features using theCreate New Feature task.

When you create new polygonfeatures, arc features and alabel point feature will be addedto the coverage automatically.

If the polygon you createoverlaps an existing polygon,the polygon feature and all arcsunderneath will be split wherefeatures overlap.

1

2

3

4

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2. Select the polygon featurethat you want to make aregion out of.

3. Click the Target layerdropdown arrow and click theregion subclass.

4. Click Editor and click Unionfrom the Editor pulldownmenu.

Creating regionfeaturesRegion feature classes arecomposite feature classes.They are built from existingprimitive features (polygons)that contain topologicalassociations.

If you try to create a new regionfeature using the Create NewFeature task, the sketch toolswill be disabled.

Since a region feature is acomposite of one or morepolygon features, you need toselect polygon features and usethe Union command to create anew region.

1

2

3

4

A new regionfeature is createdfrom both selectedpolygons.

Tip

Creating region featureclassesRegion feature classes must becreated using ArcToolbox prior toediting in ArcMap. To learn how tocreate region subclasses, see UsingArcToolbox.

Tip

Using the selectionenvironmentIt is often difficult to select polygonfeatures that already form part of aregion feature. You can use the SetSelectable Layers dialog box tomake selections easier. For moreinformation about selections, referto Using ArcMap.

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2. Select the arc features out ofwhich you want to make aroute.

3. Click the Target layerdropdown arrow and clickthe route subclass.

4. Click Editor and click Union.

Creating routefeaturesRoute feature classes arecomposite feature classescomposed of arc and sectionfeatures with an associatedmeasurement system.

Though section feature classesare not recognized by ArcMap,when you create a new routefeature from selected arcfeatures, section features willbe created automatically.

1

2

4

3

A new route featureis created fromselected arcfeatures.

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Editing coveragefeaturesThe topology of your coveragedetermines the way in whichyou edit it.

If your coverage containspolygon and/or node features,then you need to use thetopology tools to modify theshape of features. ArcMap willensure the topological integrityof your coverage by disablingtools and commands that couldbreak topological associations.

The Shared Edit tool lets youselect the boundaries sharedbetween features in a coverage.Editing shared boundariesensures that the topology ofyour coverage is maintained.For example, when you selectthe boundary shared betweentwo polygon features andreshape it using the Reshapetask, both polygon features andall associated arc features areupdated at the same time.

For more information aboutusing the topology tools, seeChapter 8, �Editing topologicalfeatures�.

Splitting a polygon

1. Click the Current Taskdropdown arrow and clickAuto Complete Polygon.

2. Click the Target layerdropdown arrow and click acoverage polygon layer.

3. Click the Sketch tool.

4. Create a sketch that startsand stops at any of theexisting polygon boundariesto enclose the new polygonyou are creating.

5. Double-click to finish thesketch.

Tip

Creating a new arc featureAnother way that you can splitpolygons is by creating a new arcfeature using the Create NewFeature task.

Suppose you wantto split this lotfeature.

1

2

4

3

The polygon wassplit, and a newpolygon, arc, andlabel were created.

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Merging adjacentpolygonsPolygon features share topo-logical associations with arcfeatures. Arc features form theperimeter of polygon featuresand the border betweenadjacent polygons. If you wantto merge two adjacent poly-gons, you need to remove thearc features that form the borderbetween them using the SharedEdit tool.

When you delete the arcfeatures, the merged polygonwill contain the attributes of thepolygon with the lowest FID.Note that the FID is differentthan the internal record number<coverage>#. The label point ofthe old polygon will not bedeleted. However, it will containthe attributes of the newpolygon. To remove labelpoints, select them using theEdit tool and click the Deletebutton.


2. Select the boundary betweenthe polygons you want tomerge.

3. Click the Delete button.

3

1

2

The border arc isremoved, and theadjacent polygonsmerged.

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2. Select a boundary of thepolygon you want to delete.

3. Click the Delete command.

Deleting apolygonWhen your ArcMap selectioncontains topo features, editingtools and commands that couldbreak the topological associa-tions that feature contains aredisabled.

For example, if you select apolygon feature using the Edittool, the Delete command isdisabled. Deleting the polygonwould break the associationthat polygon has with the arcfeatures that form its boundaryand the label feature that storesattribute information.

You can delete topo features byselecting their shared bound-aries using the Shared Edit tool.When you delete the sharedboundary of a polygon feature,the arcs and label are deleted aswell.

You also need to use the SharedEdit tool to delete arcs from acoverage that contains nodefeatures. If the arc feature youdelete contains associations tonode features that are floating,the node features will bedeleted.

Selecting a coveragepolygon with the Edit tool

will disable the Deletecommand.

1

2

3

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2. Select the boundary youwish to move.

3. Hold down the left mousebutton and drag the bound-ary to a new location.

Moving a polygonCoverage polygon featuresshare topological associationswith adjacent polygon featuresas well as arcs and labels. Eachpolygon feature is constrainedso that it cannot overlap anyother polygon feature in thesame coverage.

Given this constraint, the Movecommand is disabled. Theadded functionality of the Edittool, which lets you dragselected features, is alsodisabled. If you want to move apolygon feature, you mustmove all features that sharetopological associations withthe polygon feature by usingthe Shared Edit tool.

1

2

3

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2. Select the arc you wish tosplit.

3. Click the split command.

4. Click where you want to splitthe arc.

Splitting an arcArc features share topologicalassociations with node andpolygon features. If your arccoverage contains nodefeatures, splitting an arc featurewill create a new node feature.

You can split an arc featureusing the Split tool or bycreating a new node featureusing the Create New Featuretask.

1

2

3

4

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2. Select the node feature thatconnects the two arc fea-tures.


Mergingconnected arcsArc features that are connectedto each other and have topol-ogy contain node features. Anode feature is placed at theendpoints of each arc feature.

In order to merge two con-nected arc features together,you must delete the node thatconnects them. You need toselect that node feature usingthe Shared Edit tool to delete it.

If the node feature that youdelete is only connected to onearc feature, then deleting thenode feature will delete theassociated arc feature as well.

1

2

3

The two arcs are merged intoone feature. The attributes of thefeature with the lowest FID aremaintained.

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2. Select the arc feature youwant to delete.


Deleting an arcArc features that containtopological associations withnode and/or polygon featurescan only be deleted if youselect them using the SharedEdit tool.

The Shared Edit tool discoversthe topological associationbetween arc features and nodeand/or polygon features.

If you delete an arc feature thatborders two polygon features,then the polygon features willbe merged together. For moreinformation, see �Mergingadjacent polygons� in thisappendix.

If you delete an arc feature thatis either not connected to anyother arc feature or is con-nected to only one arc feature,then all node features thatwould otherwise be left floatingare removed.

1

2

3

The selected arc featureand related node featureare deleted.

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2. Select the arc you wish tomove.

3. Hold down the left mousebutton and drag the arc to anew location.

Moving an arcfeatureIf you want to move an arcfeature that exists in a coveragecontaining either node orpolygon feature classes, thenyou need to use the Shared Edittool.

When you move an arc featureusing the Shared Edit tool, thetopological associationsbetween arcs and nodes and/orpolygons and arcs are main-tained.

Tip

Extending an arc featureIf you select the endpoint of an arcfeature using the Shared Edit tool,you can extend its length bydragging the endpoint.

1

2

3

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2. Select the region featuresthat you want to merge.

3. Click Editor and click Merge.

Merging regionfeaturesYou can merge region featuresfrom the same coverage intoone feature. The features mustbe a part of the same regionfeature class. You could use theMerge command to combinetwo lots based on ownership. Ifthe selected lot features are notadjacent to each other, themerged feature will contain amultipart shape.

When you merge features, theoriginal features are removedand the new feature�s attributesare copied from the feature withthe lowest ID number (theoldest feature).

1

2

3

Selected region featuresare merged to form a

single lot feature.

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2. Select the route features thatyou want to merge.

3. Click Editor and click Mergefrom the Editor pulldownmenu.

Merging routefeaturesYou can merge route featuresfrom the same coverage intoone feature. The features mustbe a part of the same routefeature class.

When you merge features, theoriginal features are removedand the new feature�s attributesare copied from the feature withthe lowest ID number (theoldest feature).

1

2

3

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209

12active data frameThe data frame in a map that is currently being worked on�for example, the data frame to whichlayers are being added. The active data frame is shown in bold text in the ArcMap table of contents.

annotation1. Descriptive text used to label features. It is used for display, not for analysis.

2. A feature class used to label other features. Information stored for annotation includes a textstring, the location at which it is displayed, and a text symbol (color, font, size, and so on) fordisplay.

arc–node topologyArcs represent linear features and the borders of area features in a coverage. Every arc has a from-node, which is the first vertex in the arc, and a to-node, which is the last vertex. Nodes indicate theendpoints and intersections of arcs. They do not exist as independent features. Together theydefine the direction of the arc. Arc�node topology defines connectivity in coverages�arcs areconnected to each other if they share a common node.

ArcInfo workspaceA file-based collection of coverages, grids, TINs, or shapefiles stored as a directory of folders inthe file system.

ArcSDEA gateway to a multiuser commercial RDBMS�for example, Oracle®, Microsoft® SQL Server�,Informix®, and DB2®. ArcSDE is an open, high-performance spatial data server that employs client/server architecture to perform efficient spatial operations and manage large, shared geographicdata. Was known as SDE before 1999.

attribute1. A piece of information describing a map feature. The attributes of a ZIP Code, for example, mightinclude its area, population, and average per capita income.

2. A characteristic of a geographic feature described by numbers, characters, images, and CADdrawings, typically stored in tabular format and linked to the feature by a user-assigned identifier.For example, the attributes of a well might include depth and gallons per minute.

3. A column in a database table.

Glossary

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attribute domainA named constraint in the database. An attribute constraint canbe applied to a field of a subtype of a feature class or object classto make an attribute rule. Types of attribute domains includerange and coded-value domains.

attribute tableA DBMS or other tabular file containing rows and columns. InArcInfo, attribute tables are associated with a class of geographicfeatures such as wells or roads. Each row represents a geographicfeature. Each column represents one attribute of a feature, withthe same column representing the same attribute in each row. Seealso feature attribute table.

Attributes dialog boxA dialog box that lets you view and edit attributes of featuresyou�ve selected in ArcMap.

azimuthAn angle measured from north. Often used to define an obliquecylindrical projection or the angle of a geodesic between twopoints.

bufferA zone of a specified distance around features. Both constant-and variable-width buffers can be generated on each feature�sattribute values. The resulting buffer zones form polygons thatare either inside or outside the specified buffer distance from eachfeature. Buffers are useful for proximity analysis (for example, findall stream segments within 300 feet of a proposed logging area).

CADSee computer-aided design.

circleA geometric shape for which the distance from the center to anypoint on the edge is equal.

cluster toleranceThe distance range in which all vertices and boundaries in ashapefile or feature dataset are considered identical, orcoincident. A user-specified tolerance for the Integrate commandin ArcMap. For example, if the cluster tolerance is set to 10 mapunits, after running Integrate there will be no more than onevertex within 10 map units of another.

coincidentVertices or boundaries are coincident when they are within thecluster tolerance of one another. See also cluster tolerance.

columnThe vertical dimension of a table. A column has a name and a datatype applied to all values in the column. See also item, field, andattribute.

compressThe process of shrinking the size of a database or file. Improvesperformance by removing redundant information.

computer-aided designAn automated system for the design, drafting, and display ofgraphically oriented information.

conflictIn the versioning reconciliation process, if the same feature in theedit version and reconciliation version has been edited, thefeature is said to be in conflict. Resolving the conflict requiresyou to make the decision as to the feature�s correctrepresentation using the Conflict Resolution dialog box.

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GLOSSARY 211

connectivity1. In a geodatabase, the state of edges and junctions in a logicalnetwork that controls flow, tracing, and pathfinding.

2. The topological identification in a coverage of connected arcsby recording the from- and to-node for each arc. Arcs that share acommon node are connected. See also arc�node topology.

constraintsIn real-world databases, an object�s attributes can�t have anyparticular value based solely on what data types and ranges aparticular field type in the database allows. In reality, thepermissible values are a range or list of values.

contiguityIn coverages, the topological identification of adjacent polygonsby recording the left and right polygons of each arc. See alsopolygon�arc topology.

control pointsPoints you establish on a paper map to represent known groundpoints or specific locations. Control points are used to register apaper map before you begin digitizing features on it with adigitizer.

coordinateA set of numbers that designate location in a given referencesystem such as x,y in a planar coordinate system or x,y,z in athree-dimensional coordinate system. Coordinates representlocations on the earth�s surface relative to other locations.

coordinate system1. A reference system used to measure horizontal and verticaldistances on a planimetric map. A coordinate system is usuallydefined by a map projection; a spheroid of reference; a datum;one or more standard parallels; a central meridian; and possible

shifts in the x- and y-directions to locate x,y positions of point,line, and area features.

2. In ArcInfo, a system with units and characteristics defined by amap projection. A common coordinate system is used to spatiallyregister geographic data for the same area.

coverageA file-based vector data storage format for storing the location,shape, and attributes of geographic features. A coverage usuallyrepresents a single theme, such as soils, streams, roads, or landuse. It is one of the primary vector data storage formats forArcInfo.

A coverage stores geographic features as primary features (suchas arcs, nodes, polygons, and label points) and secondaryfeatures (such as tics, map extent, links, and annotation).Associated feature attribute tables describe and store attributesof the geographic features.

current taskDuring editing in ArcMap, a setting in the Current Taskdropdown list that determines with which task the sketchconstruction tools (Sketch, Arc, Distance�Distance, andIntersection) will work. The current task is set by clicking a task inthe Current Task dropdown list. All tasks in the Current Taskdropdown list work with a sketch that you create. For example,the Create New Feature task uses a sketch you create to make anew feature. The Extend/Trim Feature task uses a sketch youcreate to determine where the selected feature will be extended ortrimmed. The Cut Polygon Feature task uses a sketch you createto determine where the polygon will be cut.

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dangle toleranceThe minimum length allowed for dangling arcs in coverages in theArcInfo Clean process. Clean removes dangling arcs that areshorter than the dangle length. Also known as the dangle length.

dangling arcIn coverages, an arc having the same polygon on both its left andright sides and having at least one node that does not connect toany other arc. It often identifies where a polygon does not closeproperly (for example, undershoot), where arcs don�t connectproperly, or where an arc was digitized past its intersection withanother arc (for example, overshoot). A dangling arc is not alwaysan error. For example, dangling arcs can represent cul-de-sacs instreet centerline maps.

data frameIn ArcMap, a frame on the map that displays layers occupyingthe same geographic area. You may have one or more data frameson your map depending upon how you want to organize yourdata. For instance, one data frame might highlight a study area,and another might provide an overview of where the study area islocated.

data integrityMaintenance of data values according to data model and datatype. For example, to maintain integrity, numeric columns will notaccept character data.

data sourceAny geographic data, such as a coverage, shapefile, raster, orfeature class, in a geodatabase.

data typeThe characteristic of columns and variables that defines whattypes of data values they can store. Examples include character,floating point, and integer.

data viewAn all-purpose view in ArcMap for exploring, displaying, andquerying geographic data. This view hides all map elements suchas titles, North arrows, and scale bars. See also layout view.

dataset1. Any feature class, table, or collection of feature classes ortables in the geodatabase.

2. A named collection of logically related data items arranged in aprescribed manner.

decimal degreesDegrees of latitude and longitude expressed as a decimal ratherthan in degrees, minutes, and seconds.

digitizing1. To encode geographic features in digital form asx,y coordinates.

2. The process of converting the features on a paper map intodigital format. When you digitize a map, you use a digitizingtablet, or digitizer, connected to your computer and trace overfeatures with a digitizer puck, which is similar to a mouse. The x,ycoordinates of these features are automatically recorded andstored as spatial data.

digitizing modeAlso called absolute mode, digitizing mode is one of the ways inwhich a digitizing tablet operates. In digitizing mode, the locationof the tablet is mapped to a specific location on the screen.Moving the digitizer puck on the tablet surface causes the screenpointer to move to precisely the same position.

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GLOSSARY 213

distance unitsThe units�for example, feet, miles, meters, or kilometers�ArcMap uses to report measurements, dimensions of shapes, anddistance tolerances and offsets.

double precisionRefers to a high level of coordinate accuracy based on thepossible number of significant digits that can be stored for eachcoordinate. ArcInfo datasets can be stored in either single- ordouble-precision coordinates. Double-precision coverages storeup to 15 significant digits per coordinate (typically,13 to 14 significant digits), retaining the accuracy of much lessthan 1 meter at a global extent. See also single precision.

edit cacheA setting in ArcMap that causes the features visible in thecurrent map extent to be held in memory on your local machine.Designed to be used when working with large amounts of data,an edit cache results in faster editing because ArcMap doesn�thave to retrieve the data from the server.

edit sessionIn ArcMap, all editing takes place within an edit session. An editsession begins when you choose Start Editing from the Editormenu and ends when you choose Stop Editing.

Editor toolbarA toolbar that lets you create and modify features and theirattributes in ArcMap.

ellipseA geometric shape equivalent to a circle that is viewed obliquely;a flattened circle.

extentThe coordinates defining the minimum bounding rectangle (thatis, xmin, ymin and xmax, ymax) of a data source. All coordinatesfor the data source fall within this boundary.

feature1. An object class in a geodatabase that has a field of typegeometry. Features are stored in feature classes.

2. A representation of a real-world object.

3. A point, line, or polygon in a coverage or shapefile.

feature attribute tableA table used to store attribute information for a specific coveragefeature class. ArcInfo maintains the first several items of thesetables. Feature attribute tables supported for coverages includethe following:

<cover>.PAT for polygons or points<cover>.AAT for arcs<cover>.NAT for nodes<cover>.RAT for routes<cover>.SEC for sections<cover>.PAT for regions<cover>.TAT for annotation (text)

where <cover> is the coverage name.

feature class1. The conceptual representation of a geographic feature. Whenreferring to geographic features, feature classes include point,line, area, and annotation. In a geodatabase, an object class thatstores features and has a field of type geometry.

2. A classification describing the format of geographic featuresand supporting data in a coverage. Coverage feature classes forrepresenting geographic features include point, arc, node, route-system, route, section, polygon, and region. One or more

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coverage features are used to model geographic features; forexample, arcs and nodes can be used to model linear featuressuch as street centerlines. The tic, annotation, link, and boundaryfeature classes provide supporting data for coverage datamanagement and viewing.

3. The collection of all the point, line, or polygon features orannotation in a CAD dataset.

feature datasetIn geodatabases, a collection of feature classes that share thesame spatial reference. Because the feature classes share thesame spatial reference, they can participate in topologicalrelationships with each other such as in a geometric network.Several feature classes with the same geometry may be stored inthe same feature dataset. Object classes and relationship classescan also be stored in a feature dataset.

fieldA column in a table. Each field contains the values for a singleattribute.

fuzzy toleranceAn extremely small distance used to resolve inexact intersectionlocations due to the limited arithmetic precision of computers. Itdefines the resolution of a coverage resulting from the Cleanoperation or a topological overlay operation such as Union,Intersect, or Clip.

geodatabaseAn object-oriented geographic database that provides servicesfor managing geographic data. These services include validationrules, relationships, and topological associations. A geodatabasecontains feature datasets and is hosted inside of a relationaldatabase management system.

geodatabase data modelGeographic data model that represents geographic features asobjects in an object-relational database. Features are stored asrows in a table; geometry is stored in a shape field. Supportssophisticated modeling of real-world features. Objects may havecustom behavior.

georelational data modelA geographic data model that represents geographic features asan interrelated set of spatial and descriptive data. Thegeorelational model is the fundamental data model used incoverages.

indexA special data structure used in a database to speed searching forrecords in tables or spatial features in geographic datasets.ArcInfo supports both spatial and attribute indexes.

intersectThe topological integration of two spatial datasets that preservesfeatures that fall within the area common to both input datasets.See also union.

item1. A column of information in an INFO table.

2. An element in the Catalog tree. The Catalog tree can containboth geographic data sources and nongeographic elements suchas folders, folder connections, and file types.

label pointA feature class in a coverage used to represent point features andidentify polygons.

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GLOSSARY 215

layer1. A collection of similar geographic features�such as rivers,lakes, counties, or cities�of a particular area or place for displayon a map. A layer references geographic data stored in a datasource, such as a coverage, and defines how to display it. Youcan create and manage layers as you would any other type ofdata in your database.

2. A feature class in a shared geodatabase managed with SDE 3.

layout viewThe view for laying out your map in ArcMap. Layout view showsthe virtual page upon which you place and arrange geographicdata and map elements�such as titles, legends, and scale bars�for printing. See also data view.

left–right topologyThe topological data structure ArcInfo uses to representcontiguity between polygons. Left�right topology supportsanalysis functions such as adjacency. See also topology.

map1. A graphical presentation of geographic information. It containsgeographic data and other elements, such as a title, North arrow,legend, and scale bar. You can interactively display and query thegeographic data on a map and also prepare a printable map byarranging the map elements around the data in a visually pleasingmanner.

2. The document used in ArcMap that lets you display and workwith geographic data. A map contains one or more layers ofgeographic data and various supporting map elements such asscale bars. Layers on a map are contained in data frames. A dataframe has properties such as scale, projection, and extent andalso graphic properties such as where it is located on your map�spage. Some maps have one data frame, while other moreadvanced maps may have several data frames.

map documentIn ArcMap, the disk-based representation of a map. Mapdocuments can be printed or embedded into other documents.Map documents have a .mxd file extension.

map unitsThe units�for example, feet, miles, meters, or kilometers�inwhich the coordinates of spatial data are stored.

merge policyIn geodatabases, all attribute domains have a merge policyassociated with them. When two features are merged into a singlefeature in ArcMap, the merge policies dictate what happens to thevalue of the attribute to which the domain is associated. Standardmerge policies are default value, sum, and weighted average.

minimum bounding rectangleA rectangle, oriented to the x- and y-axes, that bounds ageographic feature or a geographic dataset. It is specified by twocoordinates: xmin, ymin and xmax, ymax. For example, the extentdefines a minimum bounding rectangle for a coverage.

multipart featureA feature that is composed of more than one physical part butonly references one set of attributes in the database. For example,in a layer of states, the State of Hawaii could be considered amultipart feature. Although composed of many islands, it wouldbe recorded in the database as one feature.

multipoint featureA feature that consists of more than one point but onlyreferences one set of attributes in the database. For example, asystem of oil wells might be considered a multipoint feature, asthere is a single set of attributes for the main well and multiplewell holes.

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multiuser geodatabaseA geodatabase in an RDBMS served to client applications (forexample, ArcMap) by ArcSDE. Multiuser geodatabases can bevery large and support multiple concurrent editors. Supported ona variety of commercial RDBMSs including Oracle, Microsoft SQLServer, IBM DB2, and Informix.

null valueThe absence of a value. A geographic feature for which there isno associated attribute information.

overshootThat portion of an arc digitized past its intersection with anotherarc. See also dangling arc.

panTo move the viewing window up, down, or sideways to displayareas in a geographic dataset that, at the current viewing scale,lies outside the viewing window.

parametric curveA curved segment that has only two vertices as endpoints,instead of being made of numerous vertices. You can create aparametric curve using the Arc tool or the Tangent Curvecommand in the ArcMap Editor. Also known as a true curve.

personal geodatabaseA geodatabase, usually on the same network as the clientapplication (for example, ArcMap), that supports one editor at atime. Personal geodatabases are managed in a Microsoft JetEngine database.

planar topologyRepresent collections of topological feature classes that sharegeometry among their boundaries. One or more line and polygon

feature classes that share geometry participate in a commonplanar topology. Updating shared boundaries updates all featuresin the topology.

pointA single x,y coordinate that represents a single geographicfeature such as a telephone pole.

point mode digitizingOne of two methods of digitizing features using the ArcMapEditor�s Sketch tool or from a paper map using a digitizer. Withpoint mode digitizing, you can create or edit features by digitizinga series of precise points, or vertices. Point mode digitizing iseffective when precise digitizing is required�for example, whendigitizing a perfectly straight line. See also stream mode digitizing.

polygonA two-dimensional feature representing an area such as a state orcounty.

polygon–arc topologyPAT. A coverage polygon is made up of arcs that define theboundary and a label point that links the polygon feature to anattribute record in the coverage PAT. ArcInfo stores polygonstopologically as a list of arcs and a label that make up eachpolygon.

precisionRefers to the number of significant digits used to store numbersand, in particular, coordinate values. Precision is important foraccurate feature representation, analysis, and mapping. ArcInfosupports single and double precision.

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GLOSSARY 217

preliminary topologyIn coverages, refers to incomplete region or polygon topology.Region topology defines region�arc and region�polygonrelationships. A topological region has both the region�arcrelationship and the region�polygon relationship. A preliminaryregion has the region�arc relationship but not the region�polygon relationship. In other words, preliminary regions have nopolygon topology. Polygon topology defines polygon�arc-labelpoint relationships. A preliminary polygon has the polygon�labelpoint relationship but not the polygon�arc relationship.Coverages with preliminary topology have red in their icons inthe Catalog.

projectionA mathematical formula that transforms feature locations from theearth�s curved surface to a map�s flat surface. A projectedcoordinate system employs a projection to transform locationsexpressed as latitude and longitude values to x,y coordinates.Projections cause distortions in one or more of these spatialproperties: distance, area, shape, and direction.

propertyAn attribute of an object defining one of its characteristics or anaspect of its behavior. For example, the Visible property affectswhether a control can be seen at run time. You can set a datasource�s properties using its Properties dialog box.

queryA question or request used for selecting features. A query oftenappears in the form of a statement or logical expression. InArcMap, a query contains a field, an operator, and a value.

radiusThe distance from the center to the outer edge of a circle orcircular curve.

RDBMSRelational database management system. A database managementsystem with the ability to access data organized in tabular filesthat can be related to each other by a common field (item). AnRDBMS has the capability to recombine the data items fromdifferent files, providing powerful tools for data usage. ArcSDEsupports several commercial RDBMSs.

record1. In an attribute table, a single �row� of thematic descriptors. InSQL terms, a record is analogous to a tuple.

2. A logical unit of data in a file. For example, there is one recordin the ARC file for each arc in a coverage.

relateAn operation that establishes a temporary connection betweencorresponding records in two tables using an item common toboth (for example, key attributes). Each record in one table isconnected to those records in the other table that share the samevalue for the common item. See also relational join.

relational joinThe operation of relating and physically merging two attributetables using their common item.

relationshipAn association or link between two objects in a database.Relationships can exist between spatial objects (features infeature classes) or nonspatial objects (rows in a table), orbetween spatial and nonspatial objects.

Glossary.p65 01/10/2001, 11:41 AM217


row1. A record in an attribute table. The horizontal dimension of atable composed of a set of columns containing one data itemeach.

2. A horizontal group of cells in a raster.

scanningThe process of capturing data in raster format with a device calleda scanner. Some scanners also use software to convert raster datato vector data.

segmentA line that connects vertices. For example, in a sketch of abuilding, a segment would represent one wall.

selectTo choose from a number or group of features or records; tocreate a separate set or subset.

Selectable Layers listA list on the Selection menu in ArcMap that lets you choose fromwhich layers you can select. For example, suppose you wanted toselect a large number of buildings by drawing a box around thembut selected a parcel by mistake as you drew the selection box. Toavoid this, you might uncheck the Parcels layer in the SelectableLayers list so that parcels cannot be selected.

selected setA subset of the features in a layer or records in a table. ArcMapprovides several ways to select features and records graphicallyor according to their attribute values.

selection anchorWhen editing in ArcMap, a small �x� located in the center ofselected features. The selection anchor is used when you movefeatures using snapping. It is the point on the feature or group offeatures that will be snapped to the snapping location. This isalso the point around which your selection will rotate when youuse the Rotate tool and around which your feature will scalewhen you use the Scale tool.

shapeThe characteristic appearance or visible form of a geographicobject. Geographic objects can be represented on a map usingone of three basic shapes: points, lines, or polygons.

shapefileA vector data storage format for storing the location, shape, andattributes of geographic features. A shapefile is stored in a set ofrelated files and contains one feature class.

shared boundaryA segment or boundary common to two features. For example, ina parcel database, adjacent parcels will share a boundary. Anotherexample might be a parcel that shares a boundary on one sidewith a river. The segment of the river that coincides with theparcel boundary would share the same coordinates as the parcelboundary.

shared vertexA vertex common to multiple features. For example, in a parceldatabase, adjacent parcels will share a vertex at the commoncorner.

single precisionRefers to a level of coordinate accuracy based on the number ofsignificant digits that can be stored for each coordinate. Single-

Glossary.p65 01/10/2001, 2:28 PM218

GLOSSARY 219

precision numbers store up to seven significant digits for eachcoordinate, retaining a precision of ±5 meters in an extent of1,000,000 meters. ArcInfo datasets can be stored as either single-or double-precision coordinates. See also double precision.

sketchWhen editing in ArcMap, a shape that represents a feature�sgeometry. Every existing feature on a map has an alternate form, asketch. A sketch lets you see exactly how a feature is composed,with all vertices and segments of the feature visible. To modify afeature, you must modify its sketch. To create a feature, you mustfirst create a sketch. You can only create line and polygonsketches, as points have neither vertices nor segments.

Sketches help complete the current task. For example, the CreateNew Feature task uses a sketch you create to make a new feature.The Extend/Trim Feature task uses a sketch you create todetermine where the selected feature will be extended or trimmed.The Cut Polygon Feature task uses a sketch you create todetermine where the polygon will be cut into two features.

sketch constraintsIn ArcMap editing, the angle or length limitations you can placeon segments you�re creating. These commands are available onthe Sketch tool context menu. For example, you can set a lengthconstraint that specifies that the length of the segment you�recreating will be 50 map units. At whatever angle you create thatsegment, its length will be constrained to 50 map units.

Angle constraints work in the same way. For example, you can setan angle constraint that specifies that the angle of the segmentyou�re creating will be 45 degrees measured from another featurethat already exists. At whatever length you create that segment,its angle will be constrained to 45 degrees.

sketch operationsIn ArcMap, editing operations that are performed on an existingsketch. Examples are Insert Vertex, Delete Vertex, Flip, Trim, DeleteSketch, Finish Sketch, and Finish Part. All of these operations areavailable from the Sketch context menu, which is available whenyou right-click on any part of a sketch using any editing tools.

snappingThe process of moving a feature to coincide exactly withcoordinates of another feature within a specified snappingdistance or tolerance.

snapping environmentSettings in the ArcMap Editor�s Snapping Environment windowand Editing Options dialog box that help you establish exactlocations in relation to other features. You determine thesnapping environment by setting a snapping tolerance, snappingproperties, and a snapping priority.

snapping priorityDuring ArcMap editing, the order in which snapping will occur bylayer. You can set the snapping priority by dragging the layernames in the Snapping Environment window to new locations.

snapping propertiesIn ArcMap editing, a combination of a shape to snap to and amethod for what part of the shape you will snap to. You can setyour snapping properties to have a feature snap to a vertex, edge,or endpoint of features in a specific layer. For example, a layersnapping property might let you snap to the vertices of buildings.A more generic, sketch-specific snapping property might let yousnap to the vertices of a sketch you�re creating.

Glossary.p65 01/10/2001, 11:41 AM219


snapping toleranceDuring ArcMap editing, the distance within which the pointer or afeature will snap to another location. If the location beingsnapped to (vertex, boundary, midpoint, or connection) is withinthe distance you set, the pointer will automatically snap. Forexample, if you want to snap a power line to a utility pole and thesnapping tolerance is set to 25 pixels, whenever the power linecomes within a 25-pixel range of the pole it will automatically snapto it. Snapping tolerance can be measured using either map unitsor pixels.

spatial joinA type of spatial analysis in which the attributes of features intwo different layers are joined together based on the relativelocations of the features.

spatial referenceDescribes both the projection and spatial domain extent for afeature dataset or feature class in a geodatabase.

SQLStructured Query Language. A syntax for defining andmanipulating data from a relational database. Developed by IBM®

in the 1970s, it has become an industry standard for querylanguages in most relational database management systems.

stream mode digitizingOne of the two methods of digitizing features from a paper map.Also known as streaming, stream mode digitizing provides aneasy way to capture features when you don�t require muchprecision�for example, to digitize rivers, streams, and contourlines. With stream mode, you create the first vertex of the featureand trace over the rest of the feature with the digitizer puck. Youcan also use digitize in stream mode with the ArcMap Sketch toolwhen editing �freehand�. See also point mode digitizing.

stream toleranceThe interval at which vertices are added along the feature you�redigitizing in stream mode. When streaming, vertices areautomatically created at a defined interval as you move themouse. For example, if the stream tolerance is set to 10 map units,you must move the pointer at least 10 map units before the nextvertex will be created. If you move the pointer more than 10 mapunits, there may be more space between vertices, but there willalways be a minimum interval of 10 map units. Stream tolerance ismeasured in map units. See also stream mode digitizing.

symbolA graphic pattern used to represent a feature. For example, linesymbols represent arc features; marker symbols, points; shadesymbols, polygons; and text symbols, annotation. Manycharacteristics define symbols including color, size, angle, andpattern.

symbologyThe criteria used to determine symbols for the features in a layer.A characteristic of a feature may influence the size, color, andshape of the symbol used.

tableInformation formatted in rows and columns. A set of dataelements that has a horizontal dimension (rows) and a verticaldimension (columns) in an RDBMS. A table has a specifiednumber of columns but can have any number of rows. See alsoattribute table.

table of contentsIn ArcMap, lists all the data frames and layers on the map andshows what the features in each layer represent.

Glossary.p65 01/10/2001, 11:41 AM220

GLOSSARY 221

tabular dataDescriptive information that is stored in rows and columns andcan be linked to map features.

target layerUsed in ArcMap editing, a setting in the Target layer dropdownlist that determines to which layer new features will be added. Thetarget layer is set by clicking a layer in the Target layer dropdownlist. For instance, if you set the target layer to Buildings, anyfeatures you create will be part of the Buildings layer. You mustset the target layer whenever you�re creating new features�whether you�re creating them with the Sketch tool, by copyingand pasting, or by buffering another feature.

ticRegistration or geographic control points for a coveragerepresenting known locations on the earth�s surface. Tics allowall coverage features to be recorded in a common coordinatesystem such as Universal Transverse Mercator (UTM). Tics areused to register map sheets when they are mounted on a digitizerand to transform the coordinates of a coverage, for example, fromdigitizer units (inches) to the appropriate values for a coordinatesystem (which are measured in meters for UTM).

tolerancesA coverage uses many processing tolerances (fuzzy, tic match,dangle length) and editing tolerances (weed, grain, edit distance,snap distance, and nodesnap distance). Stored in a TOL file,ArcInfo uses the values as defaults in many automation, editing,and processing operations. You can edit a coverage�s tolerancesusing its Properties dialog box in ArcCatalog.

topological associationThe spatial relationship between features that share geometrysuch as boundaries and vertices. When you edit a boundary orvertex shared by two or more features using the topology tools in

the ArcMap Editor, the shape of each of those features isupdated.

topological featureA feature that supports network connectivity that is establishedand maintained based on geometric coincidence.

topology1. In geodatabases, relationships between connected features in ageometric network or shared borders between features in a planartopology.

2. In coverages, the spatial relationships between connecting oradjacent features (for example, arcs, nodes, polygons, andpoints). The topology of an arc includes its from- and to-nodesand its left and right polygons. Topological relationships are builtfrom simple elements into complex elements: points (simplestelements), arcs (sets of connected points), areas (sets ofconnected arcs), and routes (sets of sections, which are arcs orportions of arcs). Redundant data (coordinates) is eliminatedbecause an arc may represent a linear feature, part of theboundary of an area feature, or both.

transactionA logical unit of work as defined by a user. Transactions can bedata definition (create an object), data manipulation (update anobject), or data read (select from an object).

true curveSee parametric curve.

undershootAn arc that does not extend far enough to intersect another arc.See also dangling arc.

Glossary.p65 01/10/2001, 11:41 AM221


unionA topological overlay of two polygonal spatial datasets thatpreserves features that fall within the spatial extent of either inputdataset; that is, all features from both coverages are retained. Seealso intersect.

validation ruleValidation rules can be applied to objects in the geodatabase toensure that their state is consistent with the system that thedatabase is modeling. The geodatabase supports attribute,connectivity, relationship, and custom validation rules.

versionIn geodatabases, an alternative representation of the databasethat has an owner, a description, a permission (private, protected,or public), and a parent version. Versions are not affected bychanges occurring in other versions of the database.

vertexOne of a set of ordered x,y coordinates that defines a line orpolygon feature.

virtual pageThe map page, as seen in layout view.

wizardA tool that leads a user step by step through an unusually long,difficult, or complex task.

workspaceA container for file-based geographic data. This can be a folderthat contains shapefiles, an ArcInfo workspace that containscoverages, a personal geodatabase, or an ArcSDE databaseconnection.

Glossary.p65 01/10/2001, 11:41 AM222

223

12Index A

Absolute mode. See Digitizing: in digitizing(absolute) mode

Active data framedefined 209

Adding datato be edited 60

Annotationdefined 209

Arc tool. See Editing toolsArc-node topology

defined 209ArcInfo workspace

defined 209ArcSDE

defined 209Attribute domain

defined 210Attribute tables

defined 210editing 181

Attributesadding 15, 184�185copying and pasting 73, 186defined 209deleting 185editing 58modifying 184�185undoing edits to 185viewing 182

Attributes dialog boxdefined 210

Azimuthdefined 210

B

Buffersclipping a feature using a buffer 165

Buffers (continued)creating 126defined 210

C

CAD (computer-aided design)defined 210

CAD featuresloading 43snapping when loading 45

Canceling a trace 105. See also Editing toolsCircle

defined 210Clipping features 165Cluster tolerance

defined 210described 36, 170setting 170, 171

Coincidentdefined 210

Columndefined 210

Combining features from different layers 132Compress

defined 210Computer-aided design (CAD)

defined 210Conflict

defined 210Connectivity

defined 211Constraints

defined 211Contiguity

defined 211Control points

defined 211digitizing 113establishing 112

index.p65 01/10/2001, 11:42 AM223


Coordinatedefined 211

Coordinate systemdefined 211

Copyinga line parallel to an existing line 124and pasting attributes 73and pasting features 73

Copying and pasting features 27Coverage

defined 211Coverages

composite feature classes 190creating new coverage features 192editing 53�54editing features 198primary feature classes 190secondary feature class 190simple features 191tolerances 192topo features 191topological associations 190topology 190

Creating a new arc feature 198Current task

defined 211

D

Dangle tolerancedefined 212

Dangling arcdefined 212

Dataadding for editing 60loading from a geodatabase 60stopping the drawing of 60

Data framesdefined 212editing a map with multiple 63

Data integritydefined 212

Data model. See Georelational data modelData source

defined 212Data type

defined 212Data view

defined 212Dataset

defined 212Decimal degrees

defined 212Deflection 94�95Deleting

features 72Digitizer

aligning the map on 112attaching the map to 112configuring puck buttons

for streaming 122using programming code 112, 119, 122using WinTab manager setup program 112

creating features with 111installing driver software 112setting up 22, 112

Digitizinga projected map 112defined 212digitizer tab missing 114finishing your digitizing session 26freehand 111, 117in absolute mode 23in digitizing (absolute) mode 117, 118�119in mouse (relative) mode 117in point mode 24, 117, 118�119in stream mode 25, 117, 120�121, 122installing digitizer driver software 112preparing the map 22, 112registering your map 22

Digitizing (continued)switching between digitizing and mouse

modes 117switching between point and stream modes

121using snapping 119

Digitizing modedefined 212

Digitizing tablet. See DigitizerDistance units

defined 213Distance-Distance tool. See Editing toolsDividing a line feature. See Placing points along

a lineDouble precision

defined 213Dragging features 68. See also Moving features

E

Edit cachecreating 61, 62defined 213toolbar 61zooming to extent 62

Edit sessiondefined 213starting 61stopping 63

Editinga map with more than one data frame 63adding and deleting sketch vertices 152�153adding the Editor toolbar 59combining features from different layers 132copying a line parallel to an existing line 124copying and pasting features 73coverages 53�54creating a mirror image of a feature 128creating a segment that is a parametric curve

102�103creating a sketch 56

index.p65 01/10/2001, 11:42 AM224

INDEX 225

Editing (continued)creating an edit cache 62creating buffers around features 126creating features

described 56�57from features with common areas 134using a sketch 76�77

creating line and polygon features 88�89creating multipart features

by combining features 132by merging 130

creating multipoint features 84creating parallel segments 99creating perpendicular segments 99creating point features and vertices 80�85creating segments

using angles and lengths 94�95using angles from existing segments 98�99

deleting features 72extending line features 145feature datasets 53�54flipping line features 147in layout view 63integrating data 170, 171�172merging features 130modifying features 57moving features 68�70moving sketch vertices 154�155overview of process 50�51placing points along a line feature 148reshaping a line or polygon feature. See

Reshaping featuresrotating a point's symbology 71saving edits 62scaling features 163selecting features 64�66setting the current task 14setting the Target layer 77, 80shapefiles 53�54splitting line or polygon features 138�139starting 61stopping 63

Editing (continued)tasks you can complete with a sketch 76�77trimming a line feature 142�144using the snapping environment 69�

70, 108�110vertices in a sketch 57with more than one collection of datasets

61, 192, 193, 195Editing tools

Arc tool 79, 102Distance-Distance tool 78, 83Intersection tool 78, 83Scale tool 163Shared Edit tool 173, 175, 177Sketch tool 76Split tool 138tool palette 76, 78Trace tool 79, 105

Editor toolbaradding 59defined 213diagram 52

Ellipsedefined 213

Extending line features 31, 145water lines 31, 33

Extentdefined 213

F

Featuredefined 213

Feature attribute tabledefined 213

Feature classdefined 213

Feature datasetdefined 214

Fielddefined 214

Finishing a part in a multipart feature 90Finishing a sketch

shortcut 88, 142using the Square and Finish command 89

Flipping an edge in a geometric network 147Flipping line features 147Following features. See Editing toolsFuzzy tolerance

defined 214

G

Geodatabasedefined 214loading data from 60structure of 53

Geodatabase data modeldefined 214

Georelational data modeldefined 214

I

Importing datafrom CAD drawings 42

Indexdefined 214

Integrating data 35, 170, 171�172Intersect 134

defined 214Intersection tool. See Editing toolsItem

defined 214

L

Label pointdefined 214

Layerscreating 85

index.p65 01/10/2001, 11:42 AM225


Layers (continued)defined 215setting selectable 67

Layout viewdefined 215editing in 63

Left-right topologydefined 215

Line featurescopying 124creating 17, 56, 76, 88�89, 90creating a new arc feature 192deleting coverage arcs 204extending 31, 145extending coverage arcs 205flipping 147merging connected arcs 203moving coverages arcs 205placing points along 148reshaping. See Reshaping featuressplitting 138�139splitting coverage arcs 202trimming 142�144

Loadingdata from a geodatabase 60

Loading datafrom a CAD drawing 42

M

M valuesediting 162

Mapdefined 215

Map documentdefined 215

Map unitsdefined 215

Measurementsadding vertices using 18

Measurements (continued)setting number of decimal places for reporting

74viewing 74

Merge policydefined 215

Merging features 130Minimum bounding rectangle

defined 215Mirror image 128Missing Digitizer tab 114Modifying features

by moving vertices 154�155shortcut 142

Moving featuresby dragging 29, 68by rotating 69, 71relative to their current position 69undoing a move 68using delta x,y coordinates 68�69, 69�70using the snapping environment 69

Moving vertices. See Reshaping featuresMultipart features

creating 90�91, 132defined 215described 89merging features to create 130removing parts 161shortcut for finishing a part 90

Multipoint featurescreating 86�87defined 215described 84

Multiuser geodatabasedefined 216

N

Node featurescreating 193

Null valuedefined 216

O

Overshootdefined 216

P

Pandefined 216

Parallel segments. See Segments: creatingparallel to existing

Parametric curvescreating 102�103defined 216

Pastingfeatures. See Copying and pasting features

Perpendicular segments. See Segments: creatingperpendicular to existing

Personal geodatabasedefined 216

Placing points along a line 148Planar topology

defined 216Point

defined 216Point features

creating 56, 76, 80�85, 90, 194Point mode digitizing. See Digitizing: in point

modedefined 216

Polygondefined 216

Polygon featurescreating 12, 13, 56�57, 88�89, 179, 195cutting a polygon shape out of 141deleting 200merging 199moving 201

index.p65 01/10/2001, 11:42 AM226

INDEX 227

Polygon features (continued)reshaping. See Reshaping featuressplitting 138�139, 198squaring 92�93

Polygon-arc topologydefined 216

Precisiondefined 216

Preliminary topologydefined 217

Projectiondefined 217

Propertieschanging for a sketch 159

Propertydefined 217

Q

Querydefined 217

R

Radiusdefined 217

RDBMS (relational database managementsystem)

defined 217Record

defined 217Region features

creating 196creating region feature classes 196merging 206

Registering a mapadding additional control points 115described 113�114digitizing control points 113ensuring accuracy when 116

Registering a map (continued)enterring ground coordinates 113error reporting 112, 114establishing control points 112for the first time 113removing ground coordinate records 115saving ground coordinates 113�114using existing tic files or saved coordinates

115�116Relate

defined 217Relational join

defined 217Relationship

defined 217Relative mode. See Digitizing: in mouse

(relative) modeReporting measurements. See Measurements:

setting number of decimal places forreporting

Reshaping a shared boundary 37Reshaping features

by adding vertices 152�153by deleting vertices 152�153by moving vertices 154�155using a sketch you draw 150�151

RMS error 112, 114Root mean square error. See RMS errorRotating a point�s symbology 71Rotating features 28, 69, 71Route features

creating 197merging 207

Rowdefined 218

S

Saving edits 16, 46, 62Scaling features 30, 163

Scanningdefined 218

Segment Deflection. See Editing: creatingsegments: using angles from existingsegments

Segmentscreating

at an angle from the last segment 96�97parallel to existing 19, 99parametric curves 19, 102�103perpendicular to existing 99using angles and lengths 94�95using angles from existing segments 98

defined 218Select

defined 218Selectable layers list

defined 218Selected set

defined 218Selecting features

described 64removing features from the selection 64setting selectable layers 67using a line 65using a polygon 66using the Edit tool 64using the Selection menu 66

Selection anchorand snapping 70defined 218described 65moving

when rotating or snapping a feature 70when scaling a feature 163

Shapedefined 218

Shapefiledefined 218

Shared boundarydefined 218

index.p65 01/10/2001, 11:42 AM227


Shared boundary (continued)modifying 39, 177moving 173reshaping 37, 175

Shared featurescreating 179

Shared vertexdefined 218moving 173

Single precisiondefined 218

Sketchcreating 56defined 219deleting 88described 54, 56, 76editing z- and m- values 162finishing

shortcut 88using the Square and Finish command 89

inserting vertices 160modifying 57moving vertices 154removing parts 161

Sketch constraintsdefined 219

Sketch operationsdefined 219

Sketch propertieschanging 159

Sketch tool. See Editing toolsSnapping. See also Snapping environment

defined 219setting the snapping environment 13using to split a line 138using when digitizing 119when creating a feature with shared parts

179when loading CAD features 45

Snapping environmentand moving features 69�70creating points and vertices using 80

Snapping environment (continued)defined 219described 108setting the snapping tolerance. See Snapping

tolerancewindow 106

Snapping prioritydefined 219described 110setting 110

Snapping propertiescomparing 107defined 219layer 107, 109setting 109sketch 107, 110

Snapping tolerancedefined 220described 108setting 108viewing 108

Spatial joindefined 220

Spatial referencedefined 220

Split policiessetting up 140

Split tool. See Editing toolsSplitting line features 138�139Splitting polygon features 138�139SQL

defined 220Squaring polygon features 92�93Stream mode digitizing

defined 220Stream tolerance. See also Digitizing: in stream

modedefined 220

Streaming. See Digitizing: in stream modeStretching features. See Stretching geometry

proportionately

Stretching geometry proportionately 166Subtypes 57Symbol

defined 220Symbology

defined 220

T

Tabledefined 220

Table of contentsdefined 220

Tabular datadefined 221

Tangent curve. See Parametric curvesTarget layer 57

defined 221Tic

defined 221Tolerances

defined 221Tool palette. See Editing toolsTools. See Editing toolsTopological association. See also Topology

defined 221in a geometric network 169

Topological featuredefined 221

Topology. See also Coverages: topologydefined 221editing

creating polygons with shared parts 179described 169integrating data 170modifying a shared boundary 177moving a shared vertex or boundary 173reshaping a shared boundary 175

tools 169Trace tool. See Editing tools

index.p65 01/10/2001, 11:42 AM228

INDEX 229

Tracing. See Editing toolsTransaction

defined 221Trimming line features 142�144True curve. See Parametric curves

defined 221

U

Undershootdefined 221

Union. See Combining features from differentlayers

defined 222

V

Validation ruledefined 222

VBAconfiguring digitizer puck buttons using

112, 119Vector datasets

comparing the structure of 53Version

defined 222Vertex

defined 222Vertices

adding 57, 152, 160creating 80�85

using absolute coordinates 20deleting 57, 88, 119, 152deleting multiple while streaming with a

digitizer 121moving

by dragging 154by specifying x,y coordinates 155�156relative to the current location 157�158

undoing and redoing 84, 89

Virtual pagedefined 222

Visual Basic for Applications. See VBA

W

Wizarddefined 222

Workspacesdefined 222editing a map with multiple 61

Z

Z valuesediting 162using the current control 162

index.p65 01/10/2001, 11:42 AM229

index.p65 01/10/2001, 2:09 PM230

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