Spatial Analysis, Geoprocessing, and ArcToolbox Geography 405/605

Spatial Analysis “The study of the locations and shapes of geographic features and the relationships between them.” ESRI definition “Spatial analysis is a set of methods whose results change when the locations of the objects being analyzed changes.” Longley et al. definition

Geoprocessing “A GIS operation used to manipulate GIS data. A typical geoprocessing operation takes an input dataset, performs an operation on that dataset, and returns the result of the operation as an output dataset.” ESRI definition

ArcGIS Geoprocessing Environment ArcToolbox Command Line Model Builder Scripting

ArcToolbox Toolbox Toolset Tool Models Scripts Can be accessed from ArcMap or ArcCatalog

Using the tools Tools consist of an input, an output, some parameters, and help.

Additional Help

Custom Toolboxes Users can create custom toolboxes and fill them with existing and new tools. Custom toolboxes are a convenient way to access often used tools.

Environments Set working directory Set default coordinate system Set default cluster tolerance Set spatial extent Set raster cell size

Command Line Quick and easy if you know what you are doing Can repeat the same tasks for several feature classes or rasters quickly Commands are similar to ArcINFO aml Instant feedback tells you if the processing is successful Easy to document

Model Builder Useful as a documentation tool Communicate to others your methods Drag and drop interface Chain together several processes and let it run overnight Can set variables to make the model flexible

Documentation Your model can be exported as a jpeg or as HTML You can create help for others who might use your model Model Builder uses existing tools from ArcToolbox, so interpretation is easy

Variables A variable is a parameter, such as an input file, that can be made flexible. A variable could be created that would allow the user to choose his or her own input files. Models can be static (use fixed datasets) or flexible (use variables) depending upon your needs.