Description

Returns true if this Geometry has no anomalous geometric points, such as self intersection or self tangency. For more information on the OGC's definition of geometry simplicity and validity, refer to "Ensuring OpenGIS compliancy of geometries"

	SQL-MM defines the result of ST_IsSimple(NULL) to be 0, while PostGIS returns NULL.

This method implements the OpenGIS Simple Features Implementation Specification for SQL. OGC SPEC s2.1.1.1

This method implements the SQL/MM specification: SQL-MM 3: 5.1.8

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

Examples

 SELECT ST_IsSimple(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));
 st_issimple
-------------
 t
(1 row)

 SELECT ST_IsSimple(ST_GeomFromText('LINESTRING(1 1,2 2,2 3.5,1 3,1 2,2 1)'));
 st_issimple
-------------
 f
(1 row)

See Also

ST_IsValid