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_ZMax

ST_ZMax returns the maximum z coordinate of an input geometry.

Syntax

ST_ZMax(geom)

Arguments

Return type

DOUBLE PRECISION value of the maximum z coordinate.

If geom is empty, then null is returned.

If geom is null, then null is returned.

If geom is a 2D or 3DM geometry, then null is returned.

Examples

The following SQL returns the largest z coordinate of a linestring in a 3DZ geometry.

SELECT ST_ZMax(ST_GeomFromEWKT('LINESTRING Z (0 1 2, 3 4 5, 6 7 8)'));

st_zmax
-----------
  8              

The following SQL returns the largest z coordinate of a linestring in a 4D geometry.

SELECT ST_ZMax(ST_GeomFromEWKT('LINESTRING ZM (0 1 2 3, 4 5 6 7, 8 9 10 11)'));

st_zmax
-----------
  10