Creating Spatial Columns UNIT["degree",0.017453292519943278, AUTHORITY["EPSG","9122"]], AXIS["Lat",NORTH],AXIS["Long",EAST], AUTHORITY["EPSG","4326"]] DESCRIPTION: This entry describes the SRS used for GPS systems. It has a name ( SRS_NAME ) of WGS 84 and an ID ( SRS_ID ) of 4326, which is the ID used by the European Petroleum Survey Group (EPSG). SRS definitions in the  DEFINITION  column are WKT values, represented as specified in the Open Geospatial Consortium document OGC 12-063r5. SRS_ID  values represent the same kind of values as the SRID of geometry values or passed as the SRID argument to spatial functions. SRID 0 (the unitless Cartesian plane) is special. It is always a legal spatial reference system ID and can be used in any computations on spatial data that depend on SRID values. For computations on multiple geometry values, all values must have the same SRID or an error occurs. SRS definition parsing occurs on demand when definitions are needed by GIS functions. Parsed definitions are stored in the data dictionary cache to enable reuse and avoid incurring parsing overhead for every statement that needs SRS information. To enable manipulation of SRS entries stored in the data dictionary, MySQL provides these SQL statements: • CREATE SPATIAL REFERENCE SYSTEM : See Section 13.1.19, “CREATE SPATIAL REFERENCE SYSTEM Statement” . The description for this statement includes additional information about SRS components. • DROP SPATIAL REFERENCE SYSTEM : See Section 13.1.31, “DROP SPATIAL REFERENCE SYSTEM Statement” . 11.4.6 Creating Spatial Columns MySQL provides a standard way of creating spatial columns for geometry types, for example, with  CREATE TABLE  or  ALTER TABLE . Spatial columns are supported for  MyISAM ,  InnoDB ,  NDB , and  ARCHIVE  tables. See also the notes about spatial indexes under Section 11.4.10, “Creating Spatial Indexes” . Columns with a spatial data type can have an SRID attribute, to explicitly indicate the spatial reference system (SRS) for values stored in the column. For implications of an SRID-restricted column, see Section 11.4.1, “Spatial Data Types” . •Use the  CREATE TABLE  statement to create a table with a spatial column: •Use the  ALTER TABLE  statement to add or drop a spatial column to or from an existing table: CREATE TABLE geom (g GEOMETRY); ALTER TABLE geom ADD pt POINT; ALTER TABLE geom DROP pt; 11.4.7 Populating Spatial Columns After you have created spatial columns, you can populate them with spatial data. Values should be stored in internal geometry format, but you can convert them to that format from either Well-Known Text (WKT) or Well-Known Binary (WKB) format. The following examples demonstrate how to insert geometry values into a table by converting WKT values to internal geometry format: 2062