ST_Is3D

ST_Is3D takes a geometry as an input parameter and returns 1 if the given geometry has Z coordinates. Otherwise, 0 (zero) is returned.

If the given geometry is null or is empty, null is returned.

Syntax

Parameter

geometry: A value of one of the seven distinct spatial data types that represents the geometry that is to be tested for the existence of Z coordinates.

Return type

INTEGER

Example

In this example, several geometries are created with and without Z coordinates and M coordinates (measures). ST_Is3D is then used to determine which of them contain Z coordinates.


SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse
CREATE TABLE sample_geoms (id INTEGER, geometry ST_Geometry)

INSERT INTO sample_geoms VALUES
       (1, ST_Geometry(ST_Point('point EMPTY',0)))

INSERT INTO sample_geoms VALUES
       (2, ST_Geometry(ST_Polygon('polygon((40 120, 90 120, 90 150, 40 150, 40 120))' ,0)))

INSERT INTO sample_geoms VALUES
       (3, ST_Geometry(ST_Multipoint('multipoint m (10 10 5, 50 10 6, 10 30 8)' ,0)))

INSERT INTO sample_geoms VALUES
       (4, ST_Geometry(ST_Linestring('linestring z (10 10 166, 20 10 168)',0)))

INSERT INTO sample_geoms VALUES
       (5, ST_Geometry(ST_Point('point zm (10 10 16 30)' ,0)))


SELECT id, ST_Is3d(geometry)  Is_3D
FROM sample_geoms

Results:


ID          IS_3D
----------- -----------
          1           0
          2           0
          3           0
          4           1
          5           1