ST_IsPolygonCCW - Amazon Redshift
SyntaxArgumentsReturn typeExamples
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

ST_IsPolygonCCW

ST_IsPolygonCCW returns true if the 2D projection of the input polygon or multipolygon is counterclockwise. If the input geometry is a point, linestring, multipoint, or multilinestring, then true is returned. For geometry collections, ST_IsPolygonCCW returns true if all the geometries in the collection are counterclockwise.

Syntax

ST_IsPolygonCCW(geom)

Arguments

geom

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type.

Return type

BOOLEAN

If geom is null, then null is returned.

Examples

The following SQL checks if the polygon is counterclockwise. 

SELECT ST_IsPolygonCCW(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