ST_IsPolygonCW returns true if the 2D projection of the input polygon or multipolygon is clockwise. If the input geometry is a point, linestring, multipoint, or multilinestring, then true is returned. For geometry collections, ST_IsPolygonCW returns true if all the geometries in the collection are clockwise.
Syntax
ST_IsPolygonCW(geom)
Arguments
- geom
-
A value of data type
GEOMETRYor an expression that evaluates to aGEOMETRYtype.
Return type
BOOLEAN
If geom is null, then null is returned.
Examples
The following SQL checks if the polygon is clockwise.
SELECT ST_IsPolygonCW(ST_GeomFromText('POLYGON((7 9,8 7,11 6,15 8,16 6,17 7,17 10,18 12,17 14,15 15,11 15,10 13,9 12,7 9),(9 9,10 10,11 11,11 10,10 8,9 9),(12 14,15 14,13 11,12 14))'));
st_ispolygonccw
----------
true
