ST_IsPolygonCCW
Name
ST_IsPolygonCCW — Tests if Polygons have exterior rings oriented counter-clockwise and interior rings oriented clockwise.
Synopsis
boolean
ST_IsPolygonCCW
(
geometry
geom
)
;
Description
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.
![[Note]](images/note.png)
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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. |
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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. |
Availability: 2.4.0
This function supports 3d and will not drop the z-index.
This function supports M coordinates.