ST_AsGML method

geometry-expression.ST_AsGML([ format])

Name	Type	Description
format	VARCHAR(128)	A string defining the parameters to use when converting the geometry-expression to a GML representation. If not specified, the default is 'GML'.

LONG VARCHAR Returns the GML representation of the geometry-expression.

The ST_AsGML method returns a GML string representing the geometry. A number of different formats are supported (with associated options) and the desired format is selected using the optional format parameter. If the format parameter is not specified, the default is 'GML'.

The format string defines an output format and parameters to the format. The format string has one of the following formats:

format-name

format-name(parameter1=value1;parameter2=value2;...)

parameter1=value1;parameter2=value2;...

The first format specifies the format name and no parameters. All format parameters use their default values. The second format specifies the format name and a list of named parameter values. Parameters that are not supplied use their default values. The last format specifies only parameter values, and the format name defaults to 'GML'.

The following format names may be used:

GML The Geography Markup Language format defined by ISO 19136 and the OGC.

The following format parameters can be specified:

Format Name	Parameter Name	Default Value	Allowed Values	Description
GML	Namespace	none	local Provides a default namespace attribute for the given element (in this case Point) and its sub elements. global Provides a dedicated ("gml") prefix for the given element and its sub elements. This is useful when the query is used within an aggregate operation, such that, some top level element defines the namespace for the "gml" prefix. none Provides no namespace or prefix for the given element (in this case Point) and its sub elements	The namespace parameter specifies the output format convention for namespace.
GML	SRSNameFormat	short	short Uses a short format for the spatial reference system name, for example EPSG:4326 long Uses a long format for the spatial reference system name, for example urn:x-ogc:def:crs:EPSG:4326. none Spatial reference system name attribute is not included for the geometry.	The SRSNameFormat parameter specifies the format for the srsName attribute.
GML	SRSDimension	No	Yes or No	The SRSDimension parameter specifies the number of coordinate values for the given geometry. This only applies to GML(version=3).
GML	SRSFillAll	No	Yes or No	The SRSFillAll parameter specifies whether or not SRS attributes should be propagated to child geometry elements. As an example a MultiGeometry or MultiPolygon would propagate the attributes to its child geometries.
GML	UseDeprecated	No	Yes or No	The UseDeprecated parameter only applies to GML(version=3). It is used to output older GML representations where possible. As an example a Surface may be output as a Polygon if the geometry contains no CircularStrings.
GML	Attribute	Automatically generated optional attributes	One or more attributes may be specified for the top level geometry element only	Any legal XML attributes may be specified.
GML	SubElement	Automatically generated GML sub elements	One or more sub elements may be specified for the top level geometry element only	Any legal XML elements may be specified.

Note

By default, ST_AsGML uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

SQL/MM (ISO/IEC 13249-3: 2006) 5.1.39

The following example returns the result <Point srsName="EPSG:4326"><pos>1 2 3 4</pos></Point>.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML()

The following example returns the result <Point srsName="EPSG:4326"><coordinates>1,2</coordinates></Point>.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML('GML(Version=2)')

The following returns the result <gml:Point srsName="EPSG:4326"><gml:coordinates>1,2</gml:coordinates></gml:Point>. The Namespace=global parameter provides a dedicated ("gml") prefix for the given element and its sub elements. This is useful when the query is used within an aggregate operation, such that, some top level element defines the namespace for the "gml" prefix.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML('GML(Version=2;Namespace=global)')

The following returns the result <Point srsName="EPSG:4326"><coordinates>1,2</coordinates></Point>. No namespace information is included in the output.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML('GML(Version=2;Namespace=none)')

The following returns the result <Point srsName="http://www.opengis.net/gml/srs/epsg.xml#4326"><coordinates>1,2</coordinates></Point>. The long format of the srsName attribute is used.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML('GML(Version=2;Namespace=none;SRSNameFormat=long)')

The following returns the result <Point srsName="urn:x-ogc:def:crs:EPSG:4326"><pos>1 2 3 4</pos></Point>. The long format of the srsName attribute is used and the format differs in version 3 from the version 2 format.

SELECT NEW ST_Point( 1.0, 2.0, 3.0, 4.0, 4326 ).ST_AsGML('GML(Version=3;Namespace=none;SRSNameFormat=long)')

ST_AsGML method

Syntax

Parameters

Returns

Remarks

Note

Standards and compatibility

Example