ST_ALTER_SRS procedure
Use this stored procedure to update a spatial reference system definition in the database. When this stored procedure is processed, information about the spatial reference system is updated in the DB2GSE.ST_SPATIAL_REFERENCE_SYSTEMS catalog view.
Internally, Db2® Spatial Extender stores the coordinate values as positive integers. Thus during computation, the impact of rounding errors (which are heavily dependent on the actual value for floating-point operations) can be reduced. Performance of the spatial operations can also improve significantly.
Authorization
The user ID under which the stored procedure is invoked must have DBADM authority.
Syntax
Parameter descriptions
- srs_name
- Identifies the spatial reference system. You must specify a non-null
value for this parameter.
The srs_name value is converted to uppercase unless you enclose it in double quotation marks.
The data type of this parameter is VARCHAR(128) or, if you enclose the value in double quotation marks, VARCHAR(130).
- srs_id
- Uniquely identifies the spatial reference system. This identifier
is used as an input parameter for various spatial functions. Although
you must specify a value for this parameter, the value can be null.
If this parameter is null, the numeric identifier of the spatial reference
system is not changed.
The data type of this parameter is INTEGER.
- x_offset
- Specifies the offset for all X coordinates of geometries that
are represented in this spatial reference system. Although you must
specify a value for this parameter, the value can be null. If this
parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The offset is subtracted before the scale factor x_scale is applied when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation. (WKT is well-known text, and WKB is well-known binary.)
The data type of this parameter is DOUBLE.
- x_scale
- Specifies the scale factor for all X coordinates of geometries
that are represented in this spatial reference system. Although you
must specify a value for this parameter, the value can be null. If
this parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The scale factor is applied (multiplication) after the offset x_offset is subtracted when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- y_offset
- Specifies the offset for all Y coordinates of geometries that
are represented in this spatial reference system. Although you must
specify a value for this parameter, the value can be null. If this
parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The offset is subtracted before the scale factor y_scale is applied when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- y_scale
- Specifies the scale factor for all Y coordinates of geometries
that are represented in this spatial reference system. Although you
must specify a value for this parameter, the value can be null. If
this parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The scale factor is applied (multiplication) after the offset y_offset is subtracted when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation. This scale factor must be the same as x_scale.
The data type of this parameter is DOUBLE.
- z_offset
- Specifies the offset for all Z coordinates of geometries that
are represented in this spatial reference system. Although you must
specify a value for this parameter, the value can be null. If this
parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The offset is subtracted before the scale factor z_scale is applied when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- z_scale
- Specifies the scale factor for all Z coordinates of geometries
that are represented in this spatial reference system. Although you
must specify a value for this parameter, the value can be null. If
this parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The scale factor is applied (multiplication) after the offset z_offset is subtracted when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- m_offset
- Specifies the offset for all M coordinates of geometries that
are represented in this spatial reference system. Although you must
specify a value for this parameter, the value can be null. If this
parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The offset is subtracted before the scale factor m_scale is applied when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- m_scale
- Specifies the scale factor for all M coordinates of geometries
that are represented in this spatial reference system. Although you
must specify a value for this parameter, the value can be null. If
this parameter is null, the value for this parameter in the definition
of the spatial reference system is not changed.
The scale factor is applied (multiplication) after the offset m_offset is subtracted when geometries are converted from external representations (WKT, WKB, shape) to the Db2 Spatial Extender internal representation.
The data type of this parameter is DOUBLE.
- coordsys_name
- Uniquely identifies the coordinate system on which this spatial
reference system is based. The coordinate system must be listed in
the view ST_COORDINATE_SYSTEMS. Although you must specify a value
for this parameter, the value can be null. If this parameter is null,
the coordinate system that is used for this spatial reference system
is not changed.
The coordsys_name value is converted to uppercase unless you enclose it in double quotation marks.
The data type of this parameter is VARCHAR(128) or, if you enclose the value in double quotation marks, VARCHAR(130).
- description
- Describes the spatial reference system by explaining its application.
Although you must specify a value for this parameter, the value can
be null. If this parameter is null, the description information about
the spatial reference system is not changed.
The data type of this parameter is VARCHAR(256).
Output parameters
- msg_code
- Specifies the message code that is returned from the stored procedure.
The value of this output parameter identifies the error, success,
or warning condition that was encountered during the processing of
the procedure. If this parameter value is for a success or warning
condition, the procedure finished its task. If the parameter value
is for an error condition, no changes to the database were performed.
The data type of this output parameter is INTEGER.
- msg_text
- Specifies the actual message text, associated with the message
code, that is returned from the stored procedure. The message text
can include additional information about the success, warning, or
error condition, such as where an error was encountered.
The data type of this output parameter is VARCHAR(1024).