ST_SrReg-PolarDB(PolarDB)-阿里云帮助中心

Registers a spatial reference system (SRS) and returns its spatial reference system identifier (SRID).

Syntax

integer ST_SrReg(cstring sr);
integer ST_SrReg(cstring auth_name, integer auth_id, cstring sr);

Parameters

Parameter	Type	Description
`sr`	cstring	The SRS definition string. Must be an OGC Well-Known Text (WKT) or PROJ.4 string.
`auth_name`	cstring	The authority that defines the SRS. For example, `EPSG`.
`auth_id`	integer	The SRID assigned by the authority.

How it works

The function is idempotent:

If the SRS already exists, the function returns the SRID of the existing entry without inserting a duplicate.
If the SRS does not exist, the function inserts a new record into spatial_ref_sys and returns the SRID of the new entry.

Examples

Register an existing SRS

The following example registers EPSG:4490 (China Geodetic Coordinate System 2000). Because this SRS already exists in spatial_ref_sys, the function returns its existing SRID.

SELECT ST_SrReg('GEOGCS["China Geodetic Coordinate System 2000",DATUM["China_2000",SPHEROID["CGCS2000",6378137,298.257222101,AUTHORITY["EPSG","1024"]],AUTHORITY["EPSG","1043"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4490"]]');

Output:

 st_srreg
----------
     4490

Register a new SRS with an authority name and ID

The following example registers a user-defined SRS, specifying user_defined as the authority and 100 as the authority-assigned ID. Because this SRS does not exist, the function inserts it into spatial_ref_sys and returns a new auto-assigned SRID.

SELECT ST_SrReg('user_defined', 100, 'GEOGCS["User Geodetic Coordinate System ",DATUM["China_2000",SPHEROID["CGCS2000",6378137,298.257222101,AUTHORITY["EPSG","903"]],AUTHORITY["EPSG","1043"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4491"]]');

Output:

 st_srreg
----------
    10001

Register a new SRS using a PROJ.4 string

The following example registers a new SRS using a PROJ.4 definition string. The function returns a new auto-assigned SRID.

SELECT ST_SrReg('+proj=tmerc +lat_0=1 +lon_0=112 +k=1 +x_0=19500001 +y_0=0 +ellps=krass +towgs84=24.47,-130.89,-81.56,0,0,0.13,-0.22 +units=m +no_defs');

Output:

 st_srreg
----------
    10002

Usage notes

To look up the WKT or PROJ.4 string for a standard coordinate system, use epsg.io or spatialreference.org.
The SRID returned by ST_SrReg can be used directly in other spatial functions to reference the registered coordinate system.