Geoprocessing is an integral
part of GIS analysis that creates new data from existing GIS data, from
which information can be derived to solve problems. When you need to perform
many geoprocessing operations or want to be able to easily repeat an
analysis, you can create a model to automate and keep track of your
workflow. Listed below are key points you should remember about
geoprocessing and models.
|
Geoprocessing tools used for
analysis typically fall into three categories: data extraction, overlay,
and proximity.
|
|
Geoprocessing tools are
accessible from ArcToolbox and ArcCatalog and are stored in toolsets,
which are stored in toolboxes.
|
|
Help for geoprocessing tools
can be accessed from within the tool dialog boxes.
|
|
The basic building block of a
model is a process; a process consists of a geoprocessing tool.
|
|
In a model, processes are
connected to represent and execute a geoprocessing workflow.
|
|
Models can be saved, easily
modified, and run as many times as needed to perform different analyses
and test "what if" scenarios.
|
|
Like all GIS data, models
should be documented so they can be shared with others. |
Review questions
-
What are some of the steps in
a geoprocessing workflow?
-
What do the element symbols
in a model indicate?
-
What is one way a model can
help you manage data?
-
In a typical
geoprocessing workflow, you need to determine which tools to use
and in what order; find and open the first tool, enter its
parameters, and run it; then repeat for each tool in the
sequence. After all the tools have run, you examine the final
output and make adjustments if necessary.
-
Element symbols
indicate the state of a process—whether a process is ready to
run or has already run.
-
When you add
processes to a model, you can flag their output data as
intermediate data, then delete it after the model runs.
Key terms