EPSG:6893

PROJCS["Mercator",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Mercator"],PARAMETER["central_meridian",0],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["Meter",1],PARAMETER["standard_parallel_1",0.0]]

+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +geoidgrids=egm08_25.gtx +vunits=m +no_defs 

proj4.defs("EPSG:6893","+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +geoidgrids=egm08_25.gtx +vunits=m +no_defs");

<?xml version="1.0" encoding="UTF-8"?>
 <gml:CompoundCRS xmlns:epsg="urn:x-ogp:spec:schema-xsd:EPSG:1.0:dataset" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:xlink="http://www.w3.org/1999/xlink" gml:id="iogp-crs-6893">
  <gml:metaDataProperty>
    <epsg:CommonMetaData>
      <epsg:type>compound</epsg:type>
      <epsg:informationSource>OGP</epsg:informationSource>
      <epsg:revisionDate>2015-11-25</epsg:revisionDate>
      <epsg:changes>
        <epsg:changeID xlink:href="urn:ogc:def:change-request:EPSG::2014.033" />
        <epsg:changeID xlink:href="urn:ogc:def:change-request:EPSG::2015.056" />
      </epsg:changes>
      <epsg:show>true</epsg:show>
      <epsg:isDeprecated>false</epsg:isDeprecated>
    </epsg:CommonMetaData>
  </gml:metaDataProperty>
  <gml:identifier codeSpace="IOGP">urn:ogc:def:crs:EPSG::6893</gml:identifier>
  <gml:name>WGS 84 / World Mercator +  EGM2008 height</gml:name>
  <gml:remarks>Note: for preliminary concept visualisation only. Detailed design will require use of appropriate low-distortion local projected and vertical CRSs.</gml:remarks>
  <gml:domainOfValidity xlink:href="urn:ogc:def:area:EPSG::1262" />
  <gml:scope>Visualisation of initial concept in civil engineering design (see remarks).</gml:scope>
  <gml:componentReferenceSystem xlink:href="urn:ogc:def:crs:EPSG::3395" />
  <gml:componentReferenceSystem xlink:href="urn:ogc:def:crs:EPSG::3855" />
</gml:CompoundCRS>

<?xml version="1.0" encoding="UTF-8"?>
 <gml:ProjectedCRS gml:id="ogrcrs857" xmlns:gml="http://www.opengis.net/gml/3.2">
  <gml:srsName>unnamed</gml:srsName>
  <gml:srsID>
    <gml:name gml:codeSpace="urn:ogc:def:crs:EPSG::">6893</gml:name>
  </gml:srsID>
  <gml:baseCRS>
    <gml:GeographicCRS gml:id="ogrcrs858">
      <gml:srsName>WGS 84</gml:srsName>
      <gml:srsID>
        <gml:name gml:codeSpace="urn:ogc:def:crs:EPSG::">4326</gml:name>
      </gml:srsID>
      <gml:usesEllipsoidalCS>
        <gml:EllipsoidalCS gml:id="ogrcrs859">
          <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="ogrcrs860" 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="ogrcrs861" 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="ogrcrs862">
          <gml:datumName>WGS_1984</gml:datumName>
          <gml:datumID>
            <gml:name gml:codeSpace="urn:ogc:def:datum:EPSG::">6326</gml:name>
          </gml:datumID>
          <gml:usesPrimeMeridian>
            <gml:PrimeMeridian gml:id="ogrcrs863">
              <gml:meridianName>Greenwich</gml:meridianName>
              <gml:meridianID>
                <gml:name gml:codeSpace="urn:ogc:def:meridian:EPSG::">8901</gml:name>
              </gml:meridianID>
              <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="ogrcrs864">
              <gml:ellipsoidName>WGS 84</gml:ellipsoidName>
              <gml:ellipsoidID>
                <gml:name gml:codeSpace="urn:ogc:def:ellipsoid:EPSG::">7030</gml:name>
              </gml:ellipsoidID>
              <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="ogrcrs865" />
  </gml:definedByConversion>
  <gml:usesCartesianCS>
    <gml:CartesianCS gml:id="ogrcrs866">
      <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="ogrcrs867" 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="ogrcrs868" 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>

6893=COMPD_CS["unnamed + Unnamed Vertical Datum",PROJCS["unnamed",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9108"]],AUTHORITY["EPSG","4326"]],PROJECTION["Mercator_1SP"],PARAMETER["central_meridian",0],PARAMETER["scale_factor",1],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["Meter",1],AUTHORITY["EPSG","6893"]],VERT_CS["Unnamed",VERT_DATUM["Unnamed",2005,EXTENSION["PROJ4_GRIDS","egm08_25.gtx"]],UNIT["Meter",1.0],AXIS["Up",UP]],AUTHORITY["epsg","6893"]]

PROJECTION
	"proj=merc"
	"lon_0=0"
	"k=1"
	"x_0=0"
	"y_0=0"
	"ellps=WGS84"
	"towgs84=0,0,0,0,0,0,0"
	"units=m"
	"geoidgrids=egm08_25.gtx"
	"vunits=m"
	"no_defs"
END

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +geoidgrids=egm08_25.gtx +vunits=m +no_defs">
	<Layer srs="+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +geoidgrids=egm08_25.gtx +vunits=m +no_defs">
	</Layer>
</Map>

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 6893, 'EPSG', 6893, '+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +geoidgrids=egm08_25.gtx +vunits=m +no_defs ', 'COMPD_CS["unnamed + Unnamed Vertical Datum",PROJCS["unnamed",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9108"]],AUTHORITY["EPSG","4326"]],PROJECTION["Mercator_1SP"],PARAMETER["central_meridian",0],PARAMETER["scale_factor",1],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["Meter",1],AUTHORITY["EPSG","6893"]],VERT_CS["Unnamed",VERT_DATUM["Unnamed",2005,EXTENSION["PROJ4_GRIDS","egm08_25.gtx"]],UNIT["Meter",1.0],AXIS["Up",UP]],AUTHORITY["epsg","6893"]]');

COMPD_CS["unnamed + Unnamed Vertical Datum",PROJCS["unnamed",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9108"]],AUTHORITY["EPSG","4326"]],PROJECTION["Mercator_1SP"],PARAMETER["central_meridian",0],PARAMETER["scale_factor",1],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["Meter",1],AUTHORITY["EPSG","6893"]],VERT_CS["Unnamed",VERT_DATUM["Unnamed",2005,EXTENSION["PROJ4_GRIDS","egm08_25.gtx"]],UNIT["Meter",1.0],AXIS["Up",UP]],AUTHORITY["epsg","6893"]]