Syntax

   @Circularity([<mode>])
    
Arguments

   <mode>   
   
      Determines the mode of how this function is applied. When no mode is 
      explicity set, a value of FEATURE_BOUNDARY is assumed.

      Range: FEATURE_BOUNDARY|CONVEX_HULL|ANGULARITY  

Description

   This function is responsible for computing a circularity measure for the 
   passed-in feature when the mode is FEATURE_BOUNDARY or CONVEX_HULL. As this 
   function only yields meaningful values on area-based features, it may be 
   desirable to use the CONVEX_HULL mode on line features (point features will 
   be unaffected). In this mode, the circularity of the corresponding convex 
   hull is measured rather than on the feature's geometry. In either of these 
   two modes, a value of 1 is returned for point features, and a value of 0 is 
   returned for linear features.

   The function computes how elongated a polygonal feature is. The measure 
   returned is:

      4 * PI * area / (perimeter * perimeter)

   Tip: This function is often combined with the TestFactory to select features 
   for area generalization operations.

   When the mode is set to ANGULARITY, the degree of curvature of the feature 
   will be calculated. The higher the value, the more curved its geometry. A 
   value of 0 indicates the geometry is a straight line. This mode works on 
   linear and polygonal geometries, and all other geometries will receive a 
   value of 0. The calculation of this property utilizes the angle between 
   segments and as a result linear and polygonal features must have more than 
   one segment to receive a non-zero value. Arcs are stroked into lines before 
   determining this value.