ST_SRID

Identifies the spatial reference system identifier (SRID) stored with a spatial object.

The SRID of a GEOMETRY object can only be determined when passing an SRID to either ST_GeomFromText or ST_GeomFromWKB. ST_SRID returns this stored value. SRID values of 0 to 2^32-1 are valid.

Behavior type

Syntax

ST_SRID( g )

Arguments

g

Spatial object for which you want the SRID, type GEOMETRY or GEOGRAPHY

Returns

INTEGER

Supported data types

Examples

The following examples show how to use ST_SRID.

The default SRID of a GEOMETRY object is 0:

=> SELECT ST_SRID(ST_GeomFromText(
      'POLYGON((-1 -1,2 2,0 1,-1 -1))'));
 ST_SRID
---------
 0
(1 row)

The default SRID of a GEOGRAPHY object is 4326:

=> SELECT ST_SRID(ST_GeographyFromText(
      'POLYGON((22 35,24 35,26 32,22 35))'));
 ST_SRID
---------
 4326
(1 row)