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. Karin
... View more