spatial data model: basic data typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...fully...

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Spatial Data Model: Basic Data Types 2 basic spatial data models exist vector : based on geometry of points lines Polygons raster : based on geometry of grid cells (images, bitmaps, DEMs)

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Page 1: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Spatial Data Model: Basic Data Types

2 basic spatial data models exist

vector: based on geometry of  points  lines  Polygons

raster: based on geometry of  grid cells (images, bitmaps, DEMs)

Page 2: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data

Page 3: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model Points: represent discrete point features

airports are point features

each point is stored as a coordinate pair

each point location has a record in the table

Page 4: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model Lines: represent linear features

roads are linear features

each road segment has a record in the table

Page 5: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

• Lines start and end at nodes •  line #1 goes from node #2 to node #1

• Vertices determine shape of line • Nodes and vertices are stored as coordinate

pairs

node

node

vertex

vertex

vertex

vertex

Page 6: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model Polygons: represent bounded areas

each bounded polygon has a record in the table

landforms and water are polygonal features

Page 7: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

Points are discreet Nodes

Vertices

Lines Nodes

Vertices

Arcs

Closed area (Lines + points ) = polygons

Page 8: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

Vector data formats available in ArcGIS

ESRI GeoDatabases ESRI shapefiles ArcInfo coverages and libraries CAD files (AutoCAD DWG, DXF; microstation DGN) StreetMap files Spatial Database Engine (SDE) data ASCII point coordinate data Linear measure (route) data

Page 9: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

ESRI Geodatabases Geodatabase can store many files from many source formats

1st preferred vector format in ArcGIS

Rapid display

Fully editable (coordinate and tabular) in ArcGIS

Convenient storage format

Data sets are either point or line or polygon

Page 10: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

ESRI shapefiles

2nd preferred vector format in ArcGIS Rapid display Fully editable (coordinate and tabular) in ArcGIS Simple in structure

 Do not use arc-node topology  “Connected” lines do not necessarily share a common node  Adjacent polygons do not share common bounding arcs

Data sets are either point or line or polygon

Page 11: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

•  less complex data model • polygons do not share bounding lines

Shapefile polygon spatial data model

Page 12: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

ArcInfo coverages Commonly found format (due to ArcInfo market dominance)

Data model more complex

Display more slowly in ArcGIS

Coordinate data not editable in ArcGIS

Polymorphic (point/line/polygon/route/annotation/…)

Problematic OS file structure

Page 13: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

• polygons share bounding lines • same topological rules can be built into

Geodatabase

ArcInfo coverage spatial data model

Page 14: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

ASCII coordinate data

Easy to obtain from a variety of sources  GPS  Traverse (survey)  Direct reading

OS and application independent

Vector Data Model

Page 15: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Vector Data Model

Characteristics + Features are positioned accurately

+ Shape of features can be represented correctly

+ Features are represented discretely (no fuzzy boundaries)

– Not good for representing spatially continuous phenomena

– Potentially complex data structure (especially for polygons);

- can lead to long processing time for analytical operations

Page 16: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Raster Data

Page 17: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Raster Data Model

origin is set explicitly

cell size is always known

cell references (row/column locations) are known

cell values are referenced to row/column location

values represent numerical phenomena or index codes for non-numerical phenomena

Page 18: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Raster Data Model

• digital orthophoto

• digital elevation model (DEM)

A few different types of raster data

Page 19: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Raster Data Model

Characteristics:

Rectangular grid of square cells

– Shape of discrete polygonal features generalized by cells

+ Continuous (surface) data represented easily

+ Simple data structure

Page 20: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Raster Data Model

Good at representing continuous phenomena, e.g.,

Wind speed

Elevation, slope, aspect

Chemical concentration

Likelihood of existence of a certain species

Electromagnetic reflectance (photographic or satellite imagery)

Page 21: Spatial Data Model: Basic Data Typescourses.washington.edu/gis250/lessons/proj_mgmt/datamode...Fully editable (coordinate and tabular) in ArcGIS Convenient storage format Data sets

Ecological Applications: Vol. 17, No. 2, pp. 508–526.

LINKING OCCURRENCE AND FITNESS TO PERSISTENCE: HABITAT-BASED APPROACH FOR

ENDANGERED GREATER SAGE-GROUSE

Cameron L. Aldridge and Mark S. Boyce

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Well_dst 10m cont. distance to nearest standing energy well

Rd_dst 10m cont. distance to nearest road

SB 10m cont. % sagebrush cover determined from a.p.

Crop_dst 10m cont. distance to nearest cultivated land

pCrop 10m cont. prop. of crop in a 1-km moving window

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Guest Speaker Line-up

Matthew Parsons, UW, Map Library

Peter Singleton, USFS & UW

Theresa Nogeirie, UW

Evan Girvetz, TNC & UW

Jesse Langdon, UW

Chad Wilsey, UW

Cheryl Wilder, King County

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Homework

Read “getting data into ArcGIS Maps”, “displaying layers”, “changing layer display properties”, “project and data management”, “data export”

Assignment 2. “Introduction to GIS” (due April 11)