I was given a file and asked to get an area and perimeter by utilizing the field calculator with python.

To get the area I did the following:

Area = !shape.area!

enter image description here

To get that perimeter did something very similar but got some odd numbers:

Perimeter = !shape.length!

Ultimately I am trying to calculate the PolsbyPop and since that's on a scale from 0 to 1 I knew that these numbers wouldn't work.

Using the calculate geometry function with Perimeter length (geodesic) gave the following:

enter image description here

Which in turn gives PolsbyPop values in the range I was expecting. What is the reason for the difference on the perimeter values and how I can I fix it? I have a feeling it has something to do with units but i'm not sure how to change it.

  • 3
    What coordinate system is your data in? shape.length uses the underlying coordsys. – Fezter Sep 19 at 22:44
  • Thanks, Fezter that was absolutely the problem. Sorry for the delayed reply it was a hectic last few days. Thanks again! – Eric Carlson Sep 23 at 14:18

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