FAQ: Why Are the Length and Area Fields Returning Zero?

Answer

Some storage types, such as Oracle Spatial (SDO_GEOMETRY), do not maintain an Area or Length field. This is noted in the ArcGIS Online Developer help. When queried, such as using identify in ArcMap, these fields return zero and not an error message.

If ArcObjects is being used it is necessary to detect a response of zero for Area and Length and then use the following:
Length: IPolyline.Length, IPolygon.Length
Area: IArea.Area

By using these, the length and area are calculated based on the shape object.

Code:
 
... Setup pFeature as IFeature ...
... Setup pFC as IFeatureClass for esriGeometryPolygon ...
  Dim strShapeFieldName As String
  Dim strLengthFieldName As String
  Dim strAreaFieldName As String
  

  strShapeFieldName = pFC.ShapeFieldName
  strAreaFieldName = pFC.AreaField.Name
  strLengthFieldName = pFC.LengthField.Name

  Dim pArea As IArea
  Dim pPolygon As IPolygon
  Set pArea = pFeature.Shape
  Set pPolygon = pFeature.Shape

  MsgBox "These may be zero: " & vbNewLine _
    & "  Area: " & pFeature.Value(pFeature.Fields.FindField(strAreaFieldName)) & vbNewLine _
    & "  Length: " & pFeature.Value(pFeature.Fields.FindField(strLengthFieldName))
  
  MsgBox "These will never be zero: " & vbNewLine _
    & "  Area: " & pArea.Area & vbNewLine _
    & "  Length: " & pPolygon.length

Article ID:000009504

Software:

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Why are the Length and Area fields returning zero?

Answer

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