Morphological Indicators :¶
STSpatialAttributeCommand(functionsToApply, layer, outputLayerName).execute()¶
- functionsToApply (list) – A list of one or more of the following parameters to be calculated : Area, Perimeter, NbConcavities, PerimeterConvexityDefect, AreaConvexityDefect, GraveliusIndex, MillerIndex
- layer (QgsVectorLayer) – A vector layer containg polygonal geometries
- outputLayerName (string) – If None, “layer_%s” %(functionsToApply)
A copy of the input QgsVectorLayer with attributes corresponding to the selected functions.
Though the shape are area indicators are self-explanatory, the other attributes may need an explanation :
- NbConcavities is the number of spaces left after calculating the largest convex space of the polygon
- The Perimeter Convexity Defect is the ratio between the length of the shape’s contour and that of its convex hull.
- The Area Convexity Defect is the ratio between the area shape and its convex hull.
- The Gravelius Index is an indicator of circularity
- The Miller Index is the overal direction of the shape