ArcPro 2.6 and StatePlane acting as if feet are meters

Question

I am having an chronic issue where all footage lengths, generated by using calculate geometry, are three times greater than what they should be. The shape length of the line is correct in feet. However, when I calculate length using feet as my unit the number generated will be exactly 3.28084 times greater than it should be. This is the conversion value for meters to feet. Has anyone else been experiencing this problem? It's common across my office.

Silas_Mathes · Answer

I can confirm this happens with area (acres) calculations as well.  The acreages are multiplied by 3.28^2 over what the correct value should be.  My data are in state plane coordinates with feet for units, and I use the same coordinate system for the Calculate Geometry Tool.  I'm using ArcGIS Pro 2.6.0.   If I manually calculate the field to !Shape.area@acres! the calculation is correct.

JimNoble · Answer

Linda, I have changed my maps' coordinate systems to something in UTM for the time being. UTM doesn't have this same under the hood conversion problem as StatePlane.

LindaGreen · Answer

This is happening to me too, and it's both lengths (which are universally 3.28x what they should be -- miles are 3.28x too big, meters are 3.28x too big, etc.) and areas (which are universally 10.76x too big -- acres are 10.76x too big, sqft are 10.76x too big, etc.) I've tested it on two different computers with two different files in two different State Plane zones and get the same results.

If I tell it to calculate geometry in a meter-based coordinate system, it will calculate without the error, even if the file itself remains in a State Plane system. If I make a copy of my state plane coordinate system and change the linear unit to meters in the copy, that meter-based copy will also calculate geometry correctly, although that's a bad "fix."