ST_M — Returns the M coordinate of a Point.
float ST_M(
geometry a_point)
;
Return the M coordinate of a Point, or NULL if not available. Input must be a Point.
This is not (yet) part of the OGC spec, but is listed here to complete the point coordinate extractor function list. |
This method implements the OGC Simple Features Implementation Specification for SQL 1.1.
This method implements the SQL/MM specification.
This function supports 3d and will not drop the z-index.
SELECT ST_M(ST_GeomFromEWKT('POINT(1 2 3 4)')); st_m ------ 4 (1 row)