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CREATE OR REPLACE SPATIAL REFERENCE SYSTEMsridsrs_attribute ...CREATE SPATIAL REFERENCE SYSTEM    [IF NOT EXISTS]sridsrs_attribute ...srs_attribute: {    NAME 'srs_name'  | DEFINITION 'definition'  | ORGANIZATION 'org_name' IDENTIFIED BYorg_id  | DESCRIPTION 'description'}srid,org_id:32-bit unsigned integer

This statement creates aspatial reference system (SRS) definition and stores it in the data dictionary, and requires theCREATE_SPATIAL_REFERENCE_SYSTEM privilege (orSUPER). The resulting data dictionary entry can be inspected using theINFORMATION_SCHEMAST_SPATIAL_REFERENCE_SYSTEMS table.

SRID values must be unique, so if neitherOR REPLACE norIF NOT EXISTS is specified, an error occurs if an SRS definition with the givensrid value already exists.

WithCREATE OR REPLACE syntax, any existing SRS definition with the same SRID value is replaced, unless the SRID value is used by some column in an existing table. In that case, an error occurs. For example:

mysql> CREATE OR REPLACE SPATIAL REFERENCE SYSTEM 4326 ...;ERROR 3716 (SR005): Can't modify SRID 4326. There is atleast one column depending on it.

To identify which column or columns use the SRID, use this query, replacing 4326 with the SRID of the definition you are trying to create:

SELECT * FROM INFORMATION_SCHEMA.ST_GEOMETRY_COLUMNS WHERE SRS_ID=4326;

WithCREATE ... IF NOT EXISTS syntax, any existing SRS definition with the same SRID value causes the new definition to be ignored and a warning occurs.

SRID values must be in the range of 32-bit unsigned integers, with these restrictions:

Attributes for the statement must satisfy these conditions:

Here is an exampleCREATE SPATIAL REFERENCE SYSTEM statement. TheDEFINITION value is reformatted across multiple lines for readability. (For the statement to be legal, the value actually must be given on a single line.)

CREATE SPATIAL REFERENCE SYSTEM 4120NAME 'Greek'ORGANIZATION 'EPSG' IDENTIFIED BY 4120DEFINITION  'GEOGCS["Greek",DATUM["Greek",SPHEROID["Bessel 1841",  6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],  AUTHORITY["EPSG","6120"]],PRIMEM["Greenwich",0,  AUTHORITY["EPSG","8901"]],UNIT["degree",0.017453292519943278,  AUTHORITY["EPSG","9122"]],AXIS["Lat",NORTH],AXIS["Lon",EAST],  AUTHORITY["EPSG","4120"]]';

The grammar for SRS definitions is based on the grammar defined inOpenGIS Implementation Specification: Coordinate Transformation Services, Revision 1.00, OGC 01-009, January 12, 2001, Section 7.2. This specification is available athttp://www.opengeospatial.org/standards/ct.

MySQL incorporates these changes to the specification:

If an SRS definition specifies an authority code for the projection (which is recommended), an error occurs if the definition is missing mandatory parameters. In this case, the error message indicates what the problem is. The projection methods and mandatory parameters that MySQL supports are shown inTable 15.7, “Supported Spatial Reference System Projection Methods” andTable 15.8, “Spatial Reference System Projection Parameters”.

The following table shows the projection methods that MySQL supports. MySQL permits unknown projection methods but cannot check the definition for mandatory parameters and cannot convert spatial data to or from an unknown projection. For detailed explanations of how each projection works, including formulas, seeEPSG Guidance Note 7-2.

The following table shows the projection parameters that MySQL recognizes. Recognition occurs primarily by authority code. If there is no authority code, MySQL falls back to case-insensitive string matching on the parameter name. For details about each parameter, look it up by code in theEPSG Online Registry.