Name

ST_Force3DM — Force the geometries into XYM mode.

Synopsis

geometry ST_Force3DM(geometry geomA, float Mvalue = 0.0);

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.

Code
SELECT ST_Force3DM('CIRCULARSTRING(1 1 2,2 3 2,4 5 2,6 7 2,5 6 2)');
Output
CIRCULARSTRINGM(1 1 0,2 3 0,4 5 0,6 7 0,5 6 0)
Figure
Geometry figure for visual-st-force-3dm-01
Code
SELECT 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))');
Output
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))
Figure
Geometry figure for visual-st-force-3dm-02