ST_IsPolygonCCW — Returns true if all exterior rings are oriented counter-clockwise and all interior rings are oriented clockwise.


boolean ST_IsPolygonCCW ( geometry geom );


Returns true if all polygonal components of the input geometry use a counter-clockwise orientation for their exterior ring, and a clockwise direction for all interior rings.

Returns true if the geometry has no polygonal components.


Closed linestrings are not considered polygonal components, so you would still get a true return by passing a single closed linestring no matter its orientation.


If a polygonal geometry does not use reversed orientation for interior rings (i.e., if one or more interior rings are oriented in the same direction as an exterior ring) then both ST_IsPolygonCW and ST_IsPolygonCCW will return false.

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

See Also

ST_ForcePolygonCW , ST_ForcePolygonCCW , ST_IsPolygonCW