getArea
The area of this geometry, in square metres.
Only the areal types have a meaningful area, and they are expected to compute it themselves: MPPolygonGeometry and MPMultiPolygonGeometry both override this. Every other type has no extent, and reports the nominal POINT_AREA so that the callers comparing locations by size — MPViewMaker and MPOfflineGraph sort by it, MapControlCheckAgainstGeometryTask thresholds on it — can take a mixed list without special-casing the non-areal types.
Return
this geometry's area in square metres, or POINT_AREA for the types that have no extent
Throws
if this is a POLYGON or MULTIPOLYGON geometry that does not override this method