PostGIS
Description
Returns a code indicating the ZM coordinate dimension of a geometry.
Values are: 0 = 2D, 1 = 3D-M, 2 = 3D-Z, 3 = 4D.
This function
supports 3d and will not drop the z-index.
This method
supports Circular Strings and Curves
Examples
SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRING(1 2, 3 4)'));
st_zmflag
-----------
0
SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRINGM(1 2 3, 3 4 3)'));
st_zmflag
-----------
1
SELECT ST_Zmflag(ST_GeomFromEWKT('CIRCULARSTRING(1 2 3, 3 4 3, 5 6 3)'));
st_zmflag
-----------
2
SELECT ST_Zmflag(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_zmflag
-----------
3