ST_Force4D

Signature

GEOMETRY ST_Force4D(GEOMETRY geom);
GEOMETRY ST_Force4D(GEOMETRY geom, DOUBLE zValue, DOUBLE mValue);

Description

Forces a geometry geom to be in XYZM mode.

If geom has no Z or M component, then a Z and M value are tacked on.

User can set :

a default Z value (zValue). If not specified, zValue is set to zero.
a default M value (mValue). If not specified, mValue is set to zero.

If geom has already a Z or M values, then they are untouched and just completed with the missing one.

Already XYZM geometries are returned untouched.

Examples

No effect on `XYZM` geometries

SELECT ST_Force4D('POINT ZM(-10 10 2 6)');
-- Answer:         POINT ZM(-10 10 2 6)

Adding `M` dimension

SELECT ST_Force4D('POINT(-10 10)');
-- Answer:         POINT ZM(-10 10 0 0)

SELECT ST_Force4D('LINESTRING(-10 10, 10 10)');
-- Answer:         LINESTRING ZM (-10 10 0 0, 10 10 0 0)

Specifying `mValue`

SELECT ST_Force4D('POLYGON((2 2, 10 0, 10 5, 0 5, 2 2))', 5, 3);
-- Answer:         POLYGON ZM ((2 2 5 3, 10 0 5 3, 10 5 5 3, 0 5 5 3, 2 2 5 3))

Completing existing `Z` or `M` dimensions and adding the `ZM` one

SELECT ST_Force4D('POINT Z(-10 10 12)',3, 2);
-- Answer:         POINT ZM (-10 10 12 2)

SELECT ST_Force4D('LINESTRING Z(-10 10 4, 10 10 6)', 2, 3);
-- Answer:         LINESTRING ZM (-10 10 4 3, 10 10 6 3)

SELECT ST_Force4D('POLYGON M((2 2 4, 10 0 3, 10 5 2, 0 5 1, 2 2 4))', 2, 5);
-- Answer:         POLYGON ZM ((2 2 2 4, 10 0 2 3, 10 5 2 2, 0 5 2 1, 2 2 2 4))

See also