Yay for GML! ref: http://lists.osgeo.org/pipermail/gdal-dev/2014-May/039058.html

gistfile1.txt

Proj4:

  +proj=utm +zone=36 +ellps=WGS84

GML:

<gml:ProjectedCRS gml:id="ogrcrs1">
  <gml:srsName>UTM Zone 36, Northern Hemisphere</gml:srsName>
  <gml:baseCRS>
    <gml:GeographicCRS gml:id="ogrcrs2">
      <gml:srsName>WGS 84</gml:srsName>
      <gml:usesEllipsoidalCS>
        <gml:EllipsoidalCS gml:id="ogrcrs3">
          <gml:csName>ellipsoidal</gml:csName>
          <gml:csID>
            <gml:name gml:codeSpace="urn:ogc:def:cs:EPSG::">6402</gml:name>
          </gml:csID>
          <gml:usesAxis>
            <gml:CoordinateSystemAxis gml:id="ogrcrs4" gml:uom="urn:ogc:def:uom:EPSG::9102">
              <gml:name>Geodetic latitude</gml:name>
              <gml:axisID>
                <gml:name gml:codeSpace="urn:ogc:def:axis:EPSG::">9901</gml:name>
              </gml:axisID>
              <gml:axisAbbrev>Lat</gml:axisAbbrev>
              <gml:axisDirection>north</gml:axisDirection>
            </gml:CoordinateSystemAxis>
          </gml:usesAxis>
          <gml:usesAxis>
            <gml:CoordinateSystemAxis gml:id="ogrcrs5" gml:uom="urn:ogc:def:uom:EPSG::9102">
              <gml:name>Geodetic longitude</gml:name>
              <gml:axisID>
                <gml:name gml:codeSpace="urn:ogc:def:axis:EPSG::">9902</gml:name>
              </gml:axisID>
              <gml:axisAbbrev>Lon</gml:axisAbbrev>
              <gml:axisDirection>east</gml:axisDirection>
            </gml:CoordinateSystemAxis>
          </gml:usesAxis>
        </gml:EllipsoidalCS>
      </gml:usesEllipsoidalCS>
      <gml:usesGeodeticDatum>
        <gml:GeodeticDatum gml:id="ogrcrs6">
          <gml:datumName>unknown</gml:datumName>
          <gml:usesPrimeMeridian>
            <gml:PrimeMeridian gml:id="ogrcrs7">
              <gml:meridianName>Greenwich</gml:meridianName>
              <gml:greenwichLongitude>
                <gml:angle gml:uom="urn:ogc:def:uom:EPSG::9102">0</gml:angle>
              </gml:greenwichLongitude>
            </gml:PrimeMeridian>
          </gml:usesPrimeMeridian>
          <gml:usesEllipsoid>
            <gml:Ellipsoid gml:id="ogrcrs8">
              <gml:ellipsoidName>WGS84</gml:ellipsoidName>
              <gml:semiMajorAxis gml:uom="urn:ogc:def:uom:EPSG::9001">6378137</gml:semiMajorAxis>
              <gml:secondDefiningParameter>
                <gml:inverseFlattening gml:uom="urn:ogc:def:uom:EPSG::9201">298.257223563</gml:inverseFlattening>
              </gml:secondDefiningParameter>
            </gml:Ellipsoid>
          </gml:usesEllipsoid>
        </gml:GeodeticDatum>
      </gml:usesGeodeticDatum>
    </gml:GeographicCRS>
  </gml:baseCRS>
  <gml:definedByConversion>
    <gml:Conversion gml:id="ogrcrs9">
      <gml:usesMethod xlink:href="urn:ogc:def:method:EPSG::9807" />
      <gml:usesParameterValue>
        <gml:value gml:uom="urn:ogc:def:uom:EPSG::9102">0</gml:value>
        <gml:valueOfParameter xlink:href="urn:ogc:def:parameter:EPSG::8801" />
      </gml:usesParameterValue>
      <gml:usesParameterValue>
        <gml:value gml:uom="urn:ogc:def:uom:EPSG::9102">33</gml:value>
        <gml:valueOfParameter xlink:href="urn:ogc:def:parameter:EPSG::8802" />
      </gml:usesParameterValue>
      <gml:usesParameterValue>
        <gml:value gml:uom="urn:ogc:def:uom:EPSG::9001">0.9996</gml:value>
        <gml:valueOfParameter xlink:href="urn:ogc:def:parameter:EPSG::8805" />
      </gml:usesParameterValue>
      <gml:usesParameterValue>
        <gml:value gml:uom="urn:ogc:def:uom:EPSG::9001">500000</gml:value>
        <gml:valueOfParameter xlink:href="urn:ogc:def:parameter:EPSG::8806" />
      </gml:usesParameterValue>
      <gml:usesParameterValue>
        <gml:value gml:uom="urn:ogc:def:uom:EPSG::9001">0</gml:value>
        <gml:valueOfParameter xlink:href="urn:ogc:def:parameter:EPSG::8807" />
      </gml:usesParameterValue>
    </gml:Conversion>
  </gml:definedByConversion>
  <gml:usesCartesianCS>
    <gml:CartesianCS gml:id="ogrcrs10">
      <gml:csName>Cartesian</gml:csName>
      <gml:csID>
        <gml:name gml:codeSpace="urn:ogc:def:cs:EPSG::">4400</gml:name>
      </gml:csID>
      <gml:usesAxis>
        <gml:CoordinateSystemAxis gml:id="ogrcrs11" gml:uom="urn:ogc:def:uom:EPSG::9001">
          <gml:name>Easting</gml:name>
          <gml:axisID>
            <gml:name gml:codeSpace="urn:ogc:def:axis:EPSG::">9906</gml:name>
          </gml:axisID>
          <gml:axisAbbrev>E</gml:axisAbbrev>
          <gml:axisDirection>east</gml:axisDirection>
        </gml:CoordinateSystemAxis>
      </gml:usesAxis>
      <gml:usesAxis>
        <gml:CoordinateSystemAxis gml:id="ogrcrs12" gml:uom="urn:ogc:def:uom:EPSG::9001">
          <gml:name>Northing</gml:name>
          <gml:axisID>
            <gml:name gml:codeSpace="urn:ogc:def:axis:EPSG::">9907</gml:name>
          </gml:axisID>
          <gml:axisAbbrev>N</gml:axisAbbrev>
          <gml:axisDirection>north</gml:axisDirection>
        </gml:CoordinateSystemAxis>
      </gml:usesAxis>
    </gml:CartesianCS>
  </gml:usesCartesianCS>
</gml:ProjectedCRS>