Problem: Polygons converted from lines have a negative area
When lines in a personal geodatabase feature class are converted to a polygon feature class using the 'Feature to Polygon Tool' in ArcToolBox > Data Management Tools > Features, the Shape_Area for some polygons is negative.
If the lines were digitized in a clockwise direction, the polygons created from those lines have a negative value in the Shape_Area field.
Solution or Workaround
- In ArcToolBox > Data Management Tools > Features toolbox, run the Repair Geometry Tool on the polygon feature class to correct the ring ordering of the polygons and recalculate the areas of the polygons to positive numbers.
- To avoid this problem in the future, digitize lines in a counter-clockwise direction.
This issue also occurs with both CAD and KML data imported to the geodatabase. The Repair Geometry Tool also solves the problem for line features imported under these circumstances.