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I am receiving GML as part of a larger XML message. When I receive the XML it is unmarshalled to Java objects. I have no rights to alter the schemas or the generated Java code. Therefore, I later have to marshal the OpenGIS polygon back to XML. When I try to store it in the PostGIS database, I get the following exception:

org.postgresql.util.PSQLException: ERROR: unknown spatial reference system

This is my query:

INSERT INTO test (polygon) VALUES (ST_GeomFromGML('
  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <ns1:Polygon srsName="http://metadata.ces.mil/mdr/ns/GSIP/crs/WGS84E_3D" ns1:id="P1" xmlns:ns6="http://www.isotc211.org/2005/gts" xmlns:ns5="http://release.niem.gov/niem/external/ogc/xls/1.1.0/dhs-gmo/2.1.0" xmlns:ns2="http://www.w3.org/1999/xlink" xmlns:ns1="http://www.opengis.net/gml/3.2" xmlns:ns4="http://www.isotc211.org/2005/gmd" xmlns:ns3="http://www.isotc211.org/2005/gco">
    <ns1:exterior>
      <ns1:LinearRing>
        <ns1:pos>32.23426 -110.34511 90.2</ns1:pos>
        <ns1:pos>32.23435 -110.34544 90.2</ns1:pos>
        <ns1:pos>32.23444 -110.34555 90.2</ns1:pos>
        <ns1:pos>32.23426 -110.34511 90.2</ns1:pos>
      </ns1:LinearRing>
    </ns1:exterior>
 </ns1:Polygon>', 4326))

If I try to remove the SRID from the query, I get the same exception. The column I try to store the polygon in, looks like this:

AddGeometryColumn('test', 'polygon', 4326, 'POLYGON', 3);

Any ideas? Please let me know if you need any more information.

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  • A GML pos should just have an x and y, no? Looking at the docs, I see you can insert polyhedral surfaces, but you need to specify it like <gml:posList srsDimension="3">0 0 0 0 0 1 0 1 1 0 1 0 0 0 0</gml:posList>, ie, with a srsDimension. I accept that this might seem unlikely from the error message, but worth checking. – John Powell Apr 28 '16 at 10:12
  • If you have the GML unmarshalled already, you might want to consider using JTS and insert the geometries directly as spatial objects, and avoid the overhead of GML. Just a thought :D – John Powell Apr 28 '16 at 10:14
  • I tried adding srsDimension="3", but it didn't help. However, I found out that if I change the srsName to srsName="EPSG:4269" it works. I could override that attribute, but I will try to fix it otherwise first. – fossecode Apr 28 '16 at 10:50
  • I am open to try alternative solutions. I briefly looked into JTS, and that is definitely an option. My current polygon object is a net.opengis.gml._3.PolygonType, do you have any idea on how I can convert it to a JTS polygon? – fossecode Apr 28 '16 at 10:52
  • Something like: stackoverflow.com/questions/6570017/…. I don't know how to directly cast from one type to another, but if you have the coordinates, you can simply build the geometry from that. – John Powell Apr 28 '16 at 11:28
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Solution:
Explicitly set the correct srsName gmlPolygon.getValue().setSrsName("EPSG:4326");
I also had to add srsDimension to the points since they had x, y, z:
<ns1:pos srsDimension="3">32.23435 -110.34544 90.2</ns1:pos>

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