Reprojecting an Extent object in a Python Toolbox

Question

Hello,

I am wondering how to reproject an arcpy.Extent object. I have a Python script toolboxes with a single GPExtent parameter. In the execute block, I have the following code:

ext = parameters[0].value 
srs = arcpy.SpatialReference(4326) 
ext.projectAs(srs)

When I run this, I get an error stating "RuntimeError: Object: CreateObject error creating spatial reference". Am I doing something wrong? Oddly, the above code runs fine in a notebook.

Thanks in advance!

KristinBlier · Answer

Thanks! I ran into the same issue recently, and converting the extent to a geometry fixed it. Seems to be a python toolbox bug, because the Extent projectAs() works fine from a python shell. Never would've figured that out...

Hayden Welch · Answer

You might need to assign a transformation, according to the docstring for Extent.projectAs():

If your projection requires a transformation, you can use ListTransformations  to get a list of valid transformations and pass those to the call:

from arcpy import Extent, SpatialReference, ListTransformations

ext: Extent = parameters[0].value 
srs = SpatialReference(4326)

transformation: str = ListTransformations(ext.spatialReference, srs, extent=ext)[0]

ext.projectAs(srs, transformation_name=transformation)

danretired · Answer

You might want to have a look at this link

Python Extent Calculations

it uses the extent object to make a geometry object, project it, then get the extent... seems to contradict the projectAs in the help though if the source and destination spatial references are known and correct