topic Re: Setting Linear Units or Field as the input parameter for Python Tool in ArcGIS Pro Questions

Setting Linear Units or Field as the input parameter for Python Tool

dalvon — Tue, 20 Jun 2023 19:16:03 GMT

I am creating a python tool and am trying to create a similar parameter to the input in the Buffer Tool for Distance [value or field]. I would like a drop down that has the options for Linear Unit or Field.

I have replicated the parameter data types the same way the Buffer Tool has them but it still does not work the way I want inside of my own tools GUI. Any recommendations as to how to accomplish this?

Re: Setting Linear Units or Field as the input parameter for Python Tool

AlfredBaldenweck — Tue, 20 Jun 2023 19:53:29 GMT

I think you may have to set up a field parameter, a unit parameter, and a toggle parameter, then use the tool validation page to set up the toggle to work correctly.

Then, within your tool, you can just check the toggle to choose which parameter to use.

Re: Setting Linear Units or Field as the input parameter for Python Tool

dalvon — Tue, 20 Jun 2023 20:02:57 GMT

Thats what I was thinking, but I was hoping there was another way. I tried dynamically modifying the .datatype in Tool Validation but that's not possible.

I was hoping to get the GUI to look exactly like the Buffer Distance parameter but I guess that isn't possible with python tools.

Re: Setting Linear Units or Field as the input parameter for Python Tool

AlfredBaldenweck — Thu, 17 Jul 2025 15:58:14 GMT

So, it turns out there was a way after all and I didn't know how to look for it at the time.

Make a composite parameter:

zField = arcpy.Parameter(displayName='Param0', name='zField', datatype=['GPLinearUnit', 'Field'], parameterType='Required', #multiValue = True, direction='Input')