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unit of shape_area   s k Aug 14, 2003
Re: unit of shape_area   Ianko Tchoukanski Aug 14, 2003
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Subject unit of shape_area 
Author s k 
Date Aug 14, 2003 
Message what is the unit of shape_area ? i think it is same as the map units ? is that correct ? if i have the unit as feet, will the area be square feet.

what is shape_len refers to in polygon feature class ? is it the circumference ?

when will these shape_area recalulated ? will it be automatically recalculated when somebody changes the coordinate systems or values ?

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Subject Re: unit of shape_area 
Author Ianko Tchoukanski 
Date Aug 14, 2003 
Message The units of the area are the units of your data. If the data is in decimal degrees and the dataframe is projected, you need to project the shapes in order to calculate the area in the map units (see example below).

The ICurve::Length returns the length of the polylines and the perimeter of the polygons.

If you change the dataframe projection these values will not be recalculated automatically. If you project the data and the resulting dataset is stored in a geodatabase these values will be recalculated.
Public Function ShapeArea(pShape As IGeometry) As Double
  Dim pMxDoc As IMxDocument
  Dim pMap As IMap
  Dim pArea As IArea
  Set pMxDoc = ThisDocument
  Set pMap = pMxDoc.FocusMap
  pShape.Project pMap.SpatialReference
  Set pArea = pShape
  ShapeArea = pArea.Area
End Function