Calculate field based on user defined parameters in ModelBuilder?

Question

I want to use ModelBuilder to dissolve polygons by a field whose values are concatenated strings based on 3 other fields. The general process is this:

Add field, type string, called "concat". Field calculate that field to be [field1]&""&[field2]&""&[field3]. Dissolve polygons by field "concat".

However, I want to make field1, field2, and field3 user defined. How can I do this? In the field calculate box I can pick the three fields I want but these three fields could be different on another dataset. So when running the tool I want the user to be able to pick the polygon dataset, pick the three fields for the dissolve, then hit go.

Answer 1

You will want to use user defined parameters in your model. Model Builder has "Model Parameters" that are variables to be input by the user when the tool/model is run. Here is a very good explanation of models and parameters and how to use them.

http://resources.esri.com/help/9.3/arcgisengine/java/gp_toolref/automating_your_work_with_models/working_with_variables.htm

http://resources.esri.com/help/9.3/arcgisdesktop/com/gp_toolref/automating_your_work_with_models/managing_parameters.htm

https://esriaustraliatechblog.wordpress.com/2013/11/04/creating-models-with-interactive-input-modelbuilder-10-0-10-2/

http://giscollective.org/tutorials/gis-techniques/creating-custom-tools-in-arcgis-model-builder-part-9/

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