Using a different projection to calculate areas using the Field Calculator

Question

I have a dataset that is in a WGS84_UTM projected coordinate system, can I force the Field Calculator to use another coordinate system when I use it to calculate areas using pythons !shape.area@squareyards! ?

My question is similar to checking "Use coordinate system of the data frame" in calculate geometry when the data frames projection is different; I would use this method but it does not have the option to calculate Square Yards. I could reproject the data to a new feature class, then calculate it and perform a join, or calculate the area in square feet using the data frames projection and dividing by 9, but since I will be doing this often the field calculator route would be the best way to go.

Answer 1

I would try using cursors for this type of situation. Take a look at Update Cursors and SpatialReference objects. The update cursor can replace a field calculator process in arcpy. Area tokens can be used to calculate area in another coordinate system, which can then be converted to other units. Take a look at this question.

• Pete: I was hoping I could do this in the field calculator instead of a Update Cursor, but it doesn't sound like it can be done.

Answer 2

You can simply use !shape.area@SQUAREYARDS! (or in 10.2 to be more accurate, !shape.geodesicarea@SQUAREYARDS!), wouldn't that be sufficient?

• Pete: I want to use the !shape.area@SQUAREYARDS!, but have that function calculate the area using a different projection than the one the feature class is using.