ST_AsGML function

The ST_AsGML function takes a geometry as an input parameter and returns its representation using the geography markup language.

If the given geometry is null, then null is returned.

This function can also be called as a method.

Syntax

Parameter

gmlLevel

An optional parameter specifying the GML specification level to be used for formatting the GML data to be returned. Valid values are:

2 - Use GML specification level 2 with the <gml:coordinates> tag.
3 - Use GML specification level 3 with the <gml:poslist> tag.

If no parameter is specified, the output is returned using GML specification level 2 with the <gml:coord> tag.

geometry

A value of type ST_Geometry or one of its subtypes to be converted to the corresponding GML representation.

Return type

CLOB(2G)

Example

In the following example, the lines of results have been reformatted for readability. The spacing in your results will vary according to your online display.

The following code fragment illustrates how to use the ST_AsGML function to view the GML fragment. This example populates the GML column, from the geometry column, with an ID of 2222.

SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse 

CREATE TABLE SAMPLE_POINTS (id integer, geometry ST_POINT, gml CLOB(32K))

INSERT INTO SAMPLE_POINTS (id, geometry)
VALUES
    (1100, ST_Point(10, 20, 1))

INSERT INTO sample_points(id, gml)
VALUES (2222,
  (SELECT  ST_AsGML(geometry)
   FROM    sample_points
   WHERE   id = 1100))

The following SELECT statement lists the ID and the GML representations of the geometry.

SELECT id, cast(ST_AsGML(geometry) AS varchar(110)) AS gml_fragment
FROM   sample_points
WHERE  id = 1100

Results:

SELECT id,
       cast(ST_AsGML(geometry) AS varchar(110)) AS gml,
       cast(ST_AsGML(geometry,2) AS varchar(110)) AS gml2,
       cast(ST_AsGML(geometry,3) AS varchar(110)) AS gml3
FROM   sample_points
WHERE  id = 1100

The SELECT statement returns the following result set:

ID          GML                                GML2                              GML3
----------- --------------------------------   --------------------------------  --------------------------------
       1100 <gml:Point srsName="EPSG:4269">    <gml:Point srsName="EPSG:4269">   <gml:Point srsName="EPSG:4269 
                                                                                 srsDimension="2">
            <gml:coord>                        <gml:coordinates>                 <gml:pos>
            <gml:X>10</gml:X><gml:Y>20</gml:Y> 10,20                             10,20
            </gml:coord></gml:Point>           </gml:coordinates></gml:Point>    </gml:pos></gml:Point>