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Introduction to ArcGIS for Environmental Scientists Module 3 – GIS Analysis Model Builder. Objectives. Background Create a model with existing tools and data Document a model and its components Parameterize the tools Other tips. Basics.
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Introduction to ArcGIS forEnvironmental Scientists Module 3 – GIS AnalysisModel Builder
Objectives • Background • Create a model with existing tools and data • Document a model and its components • Parameterize the tools • Other tips
Basics • Models are a series of geoprocessing tools that facilitate the automation of complex or repetitive tasks • Model Builder is a graphical interface that allows users to easily create models using existing tools and data • Requires no programming experience
Any tool, script or data can be included in the model by dragging and dropping
Output from one tool may be used as input to one or more other tools Process 1 Process 3 Process 2
Model Benefits • Models provide an easy way to interpret visual representation of the data and workflow • Models can be reused and shared, and are easy to modify if necessary • Models are much more convenient than running many tools individually • Models can be useful in project documentation
Not ready to run – input is set, tool parameters are not Run States Ready to run Already Run (tool and output are shadowed)
Documentation • Documentation for a model can be viewed in the model dialog box, ArcCatalog, or Desktop Help • On the model context menu in ArcCatalog, choose Item Description…, then click the Edit icon to add information • Basic documentation (name, label and description) can also be added on the model properties dialog
Parameters • Any information used by a tool is a parameter • Parameters can be hardcoded or set so a user can enter values • For example, it is often a good idea to set tool inputs as parameters to make models more flexible • It is also useful to make variables for some tool inputs and expose them as parameters for user input (example coming up)
Parameters • All tool parameters can be set using the Open… option on the tool’s context menu
Example Variables Shaded variables have hardcoded values
Model Dialog with no Parameters or Documentation • Some models have no parameters
Example with Parameters • Variables with a “P” are now parameters • Variable names are more meaningful
Model Dialog with Parameters and Documentation • Parameters are listed in the order they were added to the model • Order can be changed in the model properties
Tips • Working in the model builder application vs. using the model as a tool • Keep vs. delete intermediate data • Run vs. Run Entire Model • Iteration – added from Insert menu or set in the model properties • Add to Display • Export to script