ST_CoordDim

ST_CoordDim takes a geometry as an input parameter and returns the dimensionality of its coordinates.

If the given geometry does not have Z and M coordinates, the dimensionality is 2. If the given geometry has Z coordinates and no M coordinates, or if it has M coordinates and no Z coordinates, the dimensionality is 3. If it has Z and M coordinates, the dimensionality is 4. If the geometry is null, then null is returned.

Syntax

Parameter

geometry: A value of one of the seven distinct spatial data types that represents the geometry to retrieve the dimensionality from.

Return type

INTEGER

Example

The following example creates several geometries and then determines the dimensionality of their coordinates.


SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse
CREATE TABLE sample_geoms (id CHARACTER(15), geometry ST_Geometry)

INSERT INTO sample_geoms VALUES
       ('Empty Point', ST_Geometry('point EMPTY',0))

INSERT INTO sample_geoms VALUES
       ('Linestring', ST_Geometry('linestring (10 10, 15 20)',0))

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

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

INSERT INTO sample_geoms VALUES
       ('Multipoint Z', ST_Geometry('multipoint z (47 34 295, 
         23 45 678)' ,0))

INSERT INTO sample_geoms VALUES
       ('Point ZM',     ST_Geometry('point zm (10 10 16 30)' ,0))


SELECT id, ST_CoordDim(geometry)  COORDDIM
FROM sample_geoms

Results:


ID              COORDDIM
--------------- -----------
Empty Point               2
Linestring                2
Polygon                   2
Multipoint M              3
Multipoint Z              3
Point ZM                  4