ST_GeomFromText
ST_GeomFromText constructs a geometry object from a well-known text (WKT) representation of an input geometry.
ST_GeomFromText accepts 3DZ, 3DM, and 4D where the geometry type is prefixed with Z, M, or ZM, respectively.
Syntax
ST_GeomFromText(wkt_string)
ST_GeomFromText(wkt_string, srid)
Arguments
- wkt_string
-
A value of data type
VARCHAR
that is a WKT representation of a geometry.You can use the WKT keyword
EMPTY
to designate an empty point, a multipoint with an empty point, or a geometry collection with an empty point. The following example creates a multipoint with one empty and one nonempty point.ST_GeomFromEWKT('MULTIPOINT(1 0,EMPTY)');
- srid
-
A value of data type
INTEGER
that is a spatial reference identifier (SRID). If an SRID value is provided, the returned geometry has this SRID value. Otherwise, the SRID value of the returned geometry is set to zero (0).
Return type
GEOMETRY
If wkt_string or srid is null, then null is returned.
If srid is negative, then null is returned.
If wkt_string is not valid, then an error is returned.
If srid is not valid, then an error is returned.
Examples
The following SQL constructs a geometry object from the WKT representation and SRID value.
SELECT ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326);
st_geomfromtext
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0103000020E61000000100000005000000000000000000000000000000000000000000000000000000000000000000F03F000000000000F03F000000000000F03F000000000000F03F000000000000000000000000000000000000000000000000