i am trying to calculate area of several polygons using calculate geometry and i am getting the area with negative values. the projected coordinate system is Arc 1960 UTM zone 37S. i cant figure where the problem is. kindly help
Solved! Go to Solution.
This is caused by incorrect orientation of the polygons rings. As Kishor Ghatage suggests, repairing the geometry will probably solve the problem. If you work with a featureclass in a file geodatabase, you do not need to recalculate the area, this will be done automatically...
FYI, this happens when your polygon is drawn "backwards". Polygons should be drawn clockwise. If drawn counter-clockwise, you'll have negative areas. There's a similar phenomenon with polylines.
And THANK YOU to Kishor for the solution! I have a dataset created by a modeling software in which half of the polygons (17,000) were drawn backwards. Due to the negative geometry, I couldn't work with the dataset at all.
You can actually do it if you draw your polygon counterclockwise. In the particular case I was working on yesterday, yes, the polygons came from an external modeling software.