Description

Returns the coordinate dimension of the geometry. PostGIS supports 2 - (x,y) , 3 - (x,y,z) or 2D with measure - x,y,m, and 4 - 3D with measure space x,y,z,m

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

Examples

SELECT ST_NDims(ST_GeomFromText('POINT(1 1)')) As d2point,
	ST_NDims(ST_GeomFromEWKT('POINT(1 1 2)')) As d3point,
	ST_NDims(ST_GeomFromEWKT('POINTM(1 1 0.5)')) As d2pointm;

	 d2point | d3point | d2pointm
---------+---------+----------
	   2 |       3 |        3
			

See Also

ST_CoordDim, ST_Dimension, ST_GeomFromEWKT