Calculates the "circularity" of an area feature, which indicates how elongated the feature is.
A value of 1 indicates that the feature is a perfect circle, and 0 indicates that it is a line.
Parameters
Calculation Geometry
If Convex Hull is specified, the convex hull of the feature is used for the calculation; otherwise, the geometry of the feature (Feature Boundary) is used.
Note that long, thin polygons may still have a fairly high circularity value if they curve around in a U-shape and Convex Hull is specified.
The value returned is: 4 * PI * area / (perimeter * perimeter)
Circularity Attribute
The name of the attribute that will contain the angularity calculation.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click 
beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
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