ST_Multi

ST_Multi converts a geometry to the corresponding multitype. If the input geometry is already a multitype or a geometry collection, a copy of it is returned. If the input geometry is a point, linestring, or polygon, then a multipoint, multilinestring, or multipolygon, respectively, that contains the input geometry is returned.

Syntax

ST_Multi(geom)

Arguments

Return type

GEOMETRY with subtype MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, or GEOMETRYCOLLECTION.

The spatial reference system identifier (SRID) of the returned geometry is the same as that of the input geometry.

If geom is null, then null is returned.

Examples

The following SQL returns a multipoint from an input multipoint.

SELECT ST_AsEWKT(ST_Multi(ST_GeomFromText('MULTIPOINT((1 2),(3 4))', 4326)));

    st_asewkt
------------------------------------
  SRID=4326;MULTIPOINT((1 2),(3 4))             

The following SQL returns a multipoint from an input point.

SELECT ST_AsEWKT(ST_Multi(ST_GeomFromText('POINT(1 2)', 4326)));

    st_asewkt
------------------------------------
  SRID=4326;MULTIPOINT((1 2))             

The following SQL returns a geometry collection from an input geometry collection.

SELECT ST_AsEWKT(ST_Multi(ST_GeomFromText('GEOMETRYCOLLECTION(POINT(1 2),MULTIPOINT((1 2),(3 4)))', 4326)));

    st_asewkt
------------------------------------
  SRID=4326;GEOMETRYCOLLECTION(POINT(1 2),MULTIPOINT((1 2),(3 4)))