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Technical Article   Problem:  Polygons converted from lines have a negative area

Article ID: 31649
Bug Id: N/A
Software:  ArcGIS - ArcEditor 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcInfo 9.2, 9.3, 10 ArcGIS - ArcView 9.2, 9.3, 9.3.1, 10
Platforms:  Windows XP, 2003Server, Vista, 2008Server, Win 7

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.

     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.

Created: 8/22/2006
Last Modified: 1/14/2011

Article Rating: (1)
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Comments

By Anonymous - 12/21/2010 7:44 PM

I have suggested related resources/links that can enhance this article. See below.

Also affects ArcGIS 10 SP1.

By Anonymous - 12/21/2010 7:08 PM

The article needs to be updated.

Can also affect Feature Classes created from a KML file. Repair Geometry also fixes the problem in this case.

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