Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the blog post that was published on June 30, 2025.

ST_NDims

ST_NDims returns the coordinate dimension of a geometry. ST_NDims doesn't consider the topological dimension of a geometry. Instead, it returns a constant value depending on the dimension of the geometry.

Syntax

ST_NDims(geom)

Arguments

Return type

INTEGER representing the inherent dimension of geom.

If geom is null, then null is returned.

The values returned are as follows.

Examples

The following SQL returns the number of dimensions of a 2D linestring.

SELECT ST_NDims(ST_GeomFromText('LINESTRING(0 0,1 1,2 2,0 0)'));

st_ndims
-------------
 2               

The following SQL returns the number of dimensions of a 3DZ linestring.

SELECT ST_NDims(ST_GeomFromText('LINESTRING Z(0 0 3,1 1 3,2 2 3,0 0 3)'));

st_ndims
-------------
 3               

The following SQL returns the number of dimensions of a 3DM linestring.

SELECT ST_NDims(ST_GeomFromText('LINESTRING M(0 0 4,1 1 4,2 2 4,0 0 4)'));

st_ndims
-------------
 3               

The following SQL returns the number of dimensions of a 4D linestring.

SELECT ST_NDims(ST_GeomFromText('LINESTRING ZM(0 0 3 4,1 1 3 4,2 2 3 4,0 0 3 4)'));

st_ndims
-------------
 4