PostGIS
Description
Forces the geometries into XYM mode. If a geometry has no M component, then a `Mvalue` M coordinate is tacked on. If it has a Z component, then Z is removed
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3DM.
Changed: 3.1.0. Added support for supplying a non-zero M value.
This method
supports Circular Strings and Curves
Examples
--Nothing happens to an already 3D geometry
SELECT ST_AsEWKT(ST_Force3DM(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 6 2)')));
st_asewkt
------------------------------------------------
CIRCULARSTRINGM(1 1 0,2 3 0,4 5 0,6 7 0,5 6 0)
SELECT ST_AsEWKT(ST_Force3DM('POLYGON((0 0 1,0 5 1,5 0 1,0 0 1),(1 1 1,3 1 1,1 3 1,1 1 1))'));
st_asewkt
---------------------------------------------------------------
POLYGONM((0 0 0,0 5 0,5 0 0,0 0 0),(1 1 0,3 1 0,1 3 0,1 1 0))