DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS catalog view
Use the DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS catalog view to retrieve information about registered spatial reference systems.
The Spatial Extender automatically registers spatial reference systems in the Spatial Extender catalog at the following times:
- When you enable a database for spatial operations, it registers five default spatial reference systems.
- When users create additional spatial reference systems.
To get full value from the DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS catalog view, you need to understand that each spatial reference system is associated with a coordinate system. The spatial reference system is designed partly to convert coordinates derived from the coordinate system into values that Db2® can process with maximum efficiency, and partly to define the maximum possible extent of space that these coordinates can reference.
To find out the name and type of the coordinate system associated with a given spatial reference
system, query the COORDSYS_NAME and COORDSYS_TYPE columns of the DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS
catalog view. For more information about the coordinate system, query the
DB2GSE.ST_COORDINATE_SYSTEMS catalog view.
| Name | Data type | Nullable? | Content |
|---|---|---|---|
| SRS_NAME | VARCHAR(128) | No | Name of the spatial reference system. This name is unique within the database. |
| SRS_ID | INTEGER | No | numeric identifier of the spatial reference system. Each
spatial reference system has a unique numeric identifier. Spatial functions specify spatial reference systems by their numeric identifiers rather than by their names. |
| X_OFFSET | DOUBLE | No | Offset to be subtracted from all X coordinates of a geometry. The subtraction is a step in the process of converting the geometry's coordinates into values that Db2 can process with maximum efficiency. A subsequent step is to multiply the figure resulting from the subtraction by the scale factor shown in the X_SCALE column. |
| X_SCALE | DOUBLE | No | Scale factor by which to multiply the figure that results when an offset is subtracted from an X coordinate. This factor is identical to the value shown in the Y_SCALE column. |
| Y_OFFSET | DOUBLE | No | Offset to be subtracted from all Y coordinates of a geometry. The subtraction is a step in the process of converting the geometry's coordinates into values that can be processed with maximum efficiency. A subsequent step is to multiply the figure resulting from the subtraction by the scale factor shown in the Y_SCALE column. |
| Y_SCALE | DOUBLE | No | Scale factor by which to multiply the figure that results when an offset is subtracted from a Y coordinate. This factor is identical to the value shown in the X_SCALE column. |
| Z_OFFSET | DOUBLE | No | Offset to be subtracted from all Z coordinates of a geometry. The subtraction is a step in the process of converting the geometry's coordinates into values tthat can be processed with maximum efficiency. A subsequent step is to multiply the figure resulting from the subtraction by the scale factor shown in the Z_SCALE column. |
| Z_SCALE | DOUBLE | No | Scale factor by which to multiply the figure that results when an offset is subtracted from a Z coordinate. |
| M_OFFSET | DOUBLE | No | Offset to be subtracted from all measures associated with a geometry. The subtraction is a step in the process of converting the measures into values that can be processed with maximum efficiency. A subsequent step is to multiply the figure resulting from the subtraction by the scale factor shown in the M_SCALE column. |
| M_SCALE | DOUBLE | No | Scale factor by which to multiply the figure that results when an offset is subtracted from a measure. |
| MIN_X | DOUBLE | No | Minimum possible value for X coordinates in the geometries to which this spatial reference system applies. This value is derived from the values in the X_OFFSET and X_SCALE columns. |
| MAX_X | DOUBLE | No | Maximum possible value for X coordinates in the geometries to which this spatial reference system applies. This value is derived from the values in the X_OFFSET and X_SCALE columns. |
| MIN_Y | DOUBLE | No | Minimum possible value for Y coordinates in the geometries to which this spatial reference system applies. This value is derived from the values in the Y_OFFSET and Y_SCALE columns. |
| MAX_Y | DOUBLE | No | Maximum possible value for Y coordinates in the geometries to which this spatial reference system applies. This value is derived from the values in the Y_OFFSET and Y_SCALE columns. |
| MIN_Z | DOUBLE | No | Minimum possible value for Z coordinates in geometries to which this spatial reference system applies This value is derived from the values in the Z_OFFSET and Z_SCALE columns. |
| MAX_Z | DOUBLE | No | Maximum possible value for Z coordinates in geometries to which this spatial reference system applies. This value is derived from the values in the Z_OFFSET and Z_SCALE columns. |
| MIN_M | DOUBLE | No | Minimum possible value for measures that can be stored with geometries to which this spatial reference system applies. This value is derived from the values in the M_OFFSET and M_SCALE columns. |
| MAX_M | DOUBLE | No | Maximum possible value for measures that can be stored with geometries to which this spatial reference system applies. This value is derived from the values in the M_OFFSET and M_SCALE columns. |
| COORDSYS_NAME | VARCHAR(128) | No | Identifying name of the coordinate system on which this spatial reference system is based. |
| COORDSYS_TYPE | VARCHAR(128) | No | Type of the coordinate system on which this spatial reference system is based. |
| ORGANIZATION | VARCHAR(128) | Yes | Name of the organization (for example, a standards body) that defined the coordinate system on which this spatial reference system is based. ORGANIZATION is null if ORGANIZATION_COORSYS_ID is null. |
| ORGANIZATION_ COORDSYS_ID | INTEGER | Yes | Unique identifier that is assigned to the coordinate system by the organization. ORGANIZATION_COORDSYS_ID is null if ORGANIZATION is null. |
| DEFINITION | VARCHAR(2048) | No | Well-known text representation of the definition of the coordinate system. |
| DESCRIPTION | VARCHAR(256) | Yes | Description of the spatial reference system. |