Polygons converted from lines have a negative area

Description

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.

Cause

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.
  
  

  Note:
  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.