GIS CONCEPTS AND ARCGIS METHODS 3 rd Edition, July 2007 David M. Theobald, Ph.D. Warner College of Natural Resources Colorado State University
Copyright Copyright 2007 by David M. Theobald. All rights reserved. Trademarks ArcGIS, ArcMap, ArcCatalog, ArcToolbox, ArcView, ArcInfo, Spatial Analyst, Shapefile, Image Analysis, 3D Analyst, and Avenue are registered trademarks of Environmental Systems Research Institute, Inc. Publisher Conservation Planning Technologies, 1113 West Olive Street, Fort Collins, Colorado, 80521, USA. Phone: 970.980.1183. For book inquiries, please visit the following website: http://www.consplan.com Published in the United States of America ISBN 0-9679208-4-1 (paper) ii
1 Introduction to GIS and ArcGIS 1 GIS defined: what is where and why 1 Maps and more... 2 GIS functions 4 Spatial analysis 5 A brief history of GIS 8 Evolution of interface design 9 Desktop ArcGIS 11 Overview and terminology 11 ArcMap basics 13 ArcCatalog basics 21 Metadata 25 ArcToolbox and geoprocessing 27 Extensions 29 Chapter review 30 2 Geographic data 31 Representing geography 31 Where, what, and when? 31 Discrete or continuous geographic features 32 Vector 34 Geometric (non-topological) data structure 35 Topological data structure 45 Spatial indexing 54 Raster 55 GRID 61 Geodatabase raster 62 Images 62 Attribute (non-spatial) data 63 Data types 64 Tables in ArcGIS 65 Attribute fields 66 Selections and the selection set 70 Editing a table 71 Relating tables 71 Importing and exporting tables 73 iii
Chapter review 75 3 Scale, coordinate systems, and projections 77 Location, location, location... 77 Scale 79 Scale in a digital world 81 Geographic coordinate systems 82 Spheroids and datums 83 Projected coordinate systems 85 Properties and characteristics 86 Projection types 86 Distortion patterns 89 Selecting a projection 90 Commonly used projections 90 Changing coordinate systems 96 Projection definition file 96 Permanent projection 98 Temporary, on the fly, projection 99 The Global Positioning System (GPS) 99 Geocoding 103 Geocoding services 104 Chapter review 105 4 Cartography and geographic visualization 107 The art and science of cartography 107 Thematic mapping 110 General features 111 Categories 113 Mapping quantities 115 Symbolizing data 133 Advanced symbology 137 Multiple attributes map type 139 iv
Landform maps 141 Labeling maps 143 Dynamic labels 145 Annotation 146 Label expressions 147 Map layout 147 Templates 148 Exporting and printing 150 Creating interactive maps 154 Graphs 157 Chapter review 161 5 Querying spatial data 163 Selection method 164 What is here? 166 Identify 166 Interactive selection 167 How big? How long? How far? 169 Where is? Where are...? 170 Find 171 Select By Attributes 173 Definition query 177 What features are near another feature? 178 Spatial relation types 179 Examples of common selections 180 What is adjacent? 181 Chapter review 181 6 Acquiring, editing, and creating vector datasets 183 Acquiring existing datasets 184 FTP or seamless? 185 ESRI Data and Maps 185 Government sources and clearinghouses 185 v
Commercial 186 Data download lists 186 Converting a dataset 186 Sub-setting a dataset 188 Editing and topology 189 Feature-oriented digitizing 192 Feature editing basics 194 Starting an edit session 194 Setting the snapping environment 195 Adding new features 195 Common editing tasks 199 Splitting a feature 199 Deleting features 200 Modifying features 200 Removing an overlap 203 Removing a sliver polygon 203 Patching a gap 205 Integration 206 Map topology 207 Topology rules 208 Cluster tolerance 213 Topological or shared editing 213 Creating a new dataset 215 Creating and editing attribute data 217 Field calculator 218 Calculate geometry 220 Common problems with calculator expressions 221 Advanced calculator expressions 221 Chapter review 230 7 Raster analysis 231 Raster representation 231 GRIDs 235 Geodatabase raster 237 ASCII format 238 Images 239 vi
Symbology 240 Analysis environment 241 Analysis extent 243 Cell size 243 Functions 244 Local functions 245 Neighborhood functions 250 Zonal functions 254 Global functions 257 Raster/vector conversions 290 Vector to raster 290 Raster to vector 292 Image-GRID conversion 293 Advanced raster processing and map algebra 293 Raster Calculator 294 Integer and floating-point math 297 Advanced map algebra expressions 297 Randomization 304 Chapter review 321 8 Single-layer analysis 323 Geoprocessing basics 323 Auto-documentation through History 324 Batch geoprocessing 325 Summarizing attributes 325 Basic statistics 325 Summarize 328 Measurement 329 Number 329 Area 329 Length 330 Shape 331 Fragmentation 333 Distance 337 Pattern 339 Proximity analysis 342 Buffering 343 vii
Variable buffers 345 Neighborhoods 346 Transformations 347 Feature center and centroid 348 Dissolve 350 Eliminate 350 Generalization 351 Resampling 352 Chapter review 353 9 Dual-layer analysis 355 Overlay analysis 355 Clip 359 Intersect 361 Union 363 Merge/append 364 Join by location 365 Nearest feature 367 Intersecting a feature 367 Inside a polygon 368 Chapter review 368 10 Spatial modeling and geoprocessing 369 Modeling concepts 370 Flow charts 370 Boolean model 373 Arithmetic model 375 Weighted arithmetic model 378 Evolution of user interfaces in GIS 380 ModelBuilder 381 Modeling accessibility -- an illustration of iterative modeling 382 Advanced ModelBuilder techniques 395 Programming scripts using Python 396 Why use Python? 396 Basics of Python programming 397 viii
Arguments 407 Connecting Python with ArcGIS 408 Debugging tips 421 Ten ways to improve your ArcGIS experience 422 ix