GIS CONCEPTS AND ARCGIS METHODS 2 nd Edition, July 2005 David M. Theobald, Ph.D. Natural Resource Ecology Laboratory Colorado State University
Copyright Copyright 2005 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 0-9679208-3-3 (paper)
CHAPTER 1 Introduction to GIS and ArcGIS 1 What is special about GIS? 1 GIS defined 2 Maps and more... 3 Spatial analysis 5 Evolution of interface design 8 Desktop ArcGIS 9 Overview 9 ArcMap basics 11 ArcCatalog basics 19 Geoprocessing 25 Extensions 27 Key changes in v9 28 Key changes in v8 29 File and path names in ArcGIS 32 CHAPTER 2 Data models and structures 35 Representing geographic features 35 Where, what, and when 36 Human cognition of geographic features 36 Feature data structures 38 Geometric data structure 38 Topological data structure 44 Network 50 Surface 53 Object-oriented data structure 54 Spatial index 59 Supported feature data structures 61 Field data structures 62 Non-spatial (attribute) data 63 Data types 64 Relating tables 66 Tables in ArcGIS 68 GRID attribute table 76 Importing spatial data 77 Importing feature data 78 iii
CHAPTER 3 Coordinate systems, projections, and GPS 81 Location, location, location... 81 Scale 82 Scale in a digital world 84 Geographic coordinate systems 86 Spheroids and datums 87 The Global Positioning System (GPS) 88 Projected coordinate systems 91 Properties and characteristics 91 Projection types 92 Distortion patterns 95 Selecting a projection 96 Commonly used projections 96 Changing coordinate systems 102 Projection definition file 102 Permanent projection 104 Temporary, on the fly, projection 105 CHAPTER 4 Visualization of spatial data 107 Overview 107 Thematic mapping 110 Features map type 111 Categories map type 113 Quantities map type 115 Charts 129 Multiple attributes map type 130 Symbology 130 Styles 138 Landform maps 138 Labeling maps 141 Dynamic labels 142 Annotation 143 Graphs 143 Map layout 147 Templates 148 Exporting and printing 150 iv
Creating interactive maps 153 CHAPTER 5 Querying a map 157 Overview 157 Selection method 157 Where is? Where are...? 159 Find 159 Select by attributes (SQL) 160 Definition query 165 What is here? 166 Identify 166 Interactive selection 167 How big? 169 How far? 170 What features are near another feature? 171 Spatial relation types 172 Buffered selections 173 Examples of common selections 173 What is adjacent? 174 CHAPTER 6 Creating and editing feature data 177 Overview 177 Creating a new dataset 177 Creating a new dataset 178 Converting a dataset 181 Sub-setting a dataset 182 Topology revisited 183 Feature-oriented editing 186 Feature editing basics 188 Starting an edit session 188 Snapping environment 189 Common editing tasks 190 Adding new features 190 Splitting a feature 194 Deleting features 195 v
Modifying features 195 Removing an overlap 198 Removing a sliver polygon 198 Patching a gap 200 Integration 200 Changing feature order 202 Map topology 202 Topology rules 203 Cluster tolerance 207 Topological or shared editing 207 Geocoding 209 Geocoding services 211 Editing attribute data 212 Common problems with calculator expressions 214 Advanced calculator expressions 214 CHAPTER 7 Raster basics 223 Overview 223 Raster representation 223 GRID 225 Images 231 Raster symbology 234 Analysis environment 236 Analysis extent 237 Cell size 238 Raster-vector conversion 239 Vector to raster 240 Raster to vector 242 Image-GRID conversion 243 Local functions 243 Cell Statistics 244 Reclassification 246 Focal functions 248 Neighborhood functions 250 Neighborhood statistics 251 Zonal functions 252 Zonal statistics 253 vi
Global functions 254 Distance 254 Density 263 Surface analysis 265 Surface generation (interpolation) 277 CHAPTER 8 Advanced raster analysis 285 Overview 285 Advanced raster analysis 286 Map algebra 286 Raster Calculator 287 Integer and floating-point math 289 Advanced map algebra expressions 290 Importing raster data 313 CHAPTER 9 Single-layer analysis 315 Overview 315 Summarizing attributes 315 Basic statistics 316 Summarize 318 Measurement 319 Number 319 Area 320 Length 320 Shape 321 Fragmentation 323 Distance 328 Pattern 330 Proximity analysis 334 Buffering 335 Variable buffers 338 Neighborhoods 340 Transformations 340 Feature center and centroid 341 Dissolve 343 Eliminate 343 vii
Generalization 344 Resampling 344 CHAPTER 10 Dual-layer analysis 347 Overview 347 Overlay analysis 347 Clip 349 Intersect 353 Union 355 Merge 357 Join by location 358 Nearest feature 359 Intersecting a feature 359 Inside a polygon 360 CHAPTER 11 Spatial modeling and geoprocessing 361 Overview 361 Modeling concepts 362 Flow charts 362 Boolean model 365 Arithmetic model 367 Weighted arithmetic model 370 Evolution of user interfaces in GIS 372 ModelBuilder 374 Basics of ModelBuilder 374 Modeling accessibility -- an illustration of iterative modeling 390 Programming models using Python 403 Why use Python? 403 Basics of Python programming 405 Arguments 415 Connecting Python with ArcGIS 416 Debugging tips 428 Ten ways to improve your ArcGIS experience 429 viii