NR 322: Single Layer Analysis

Jim Graham

Fall 2008

Chapter 8 & 9

Geometric Calculations

Add A Field

• Add a double

Polyline Geometry

• Use an “Equidistant Projection”

Polygon Geometry

• Use an “Equal Area” Projection

Centroid

Making Centroids

• Add fields for X and Y

• Use “Calculate Geometry” to add the X and Y coordinates of the centroid

• Open the dbf in Excel

• Save the dbf to a tab-delimited text file

• Use “Tools -> Add X Y Data” to add the text file as points

Buffering

• Creates polygons around existing vector features

Buffering

• ArcToolbox -> Analysis -> Proximity -> Buffer

Buffering

• Create a polygon Shapefile for buffers

• Open the “Editor” toolbar

• Start an edit session

• Select a feature using the edit tool

• Task: Create new feature

• Target: <your new shapefile>

• Select “Buffer” from the “Editor” menu

• Enter the distance for the buffer to add around the feature

Dissolving

• ArcToolbox -> Data Management Tools -> Generalization -> Dissolve

• Combines features based on a common attribute value

Clip

• ArcToolbox -> Analysis Tools -> Extract -> Clip

• ArcToolbox -> Overlay -> Erase

• ArcToolbox -> Data Management Tools -> Raster -> Clip

Intersection

• ArcToolbox -> Analysis Tools -> Overlay -> Intersect

• ArcToolbox -> Spatial Analysis Tools -> Local -> Combine

Generalization

• ArcToolbox -> Data Management Tools -> Generalization -> …

Generalization (100 meters)

Original Generalized to 100 meters

Generalization (1000 meters)

Original Generalized to 1000 meters