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GXP: Custom Ellipsoids and Map Projections

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Trent Hare edited this page Apr 13, 2022 · 1 revision

Several files must be updated to include new and/or update ellipsoids in GXP and pre-defined map projections. The files to update and their parameters are well defined in the GXP help documents. This can be found the installation directory, generally: "C:\Program Files\BAE SYSTEMS\SOCET GXP 4.3.0\Config\Help\sgxp\socetgxp.htm".

Within \SOCET GXP 4.3.0\Config\Cs we will need to edit:

  • ellipsoid.xml
  • geodetic.xml
  • CoordinateSystems.xml (to define pre-defined map projection, e.g. Polar Stereographic)

For this example we are add Mars set to the IAU Sphere - 3396190.0

  • ellipsoid.xml
    <Ellipsoid ellipsoid_code="MS">
       <ellipsoid_name v="Mars 2000 IAU Sphere"/>
       <equatorial_radius v="3396190.0"/>
       <flattening v="0.0000000000"/>
       <ellipsoid_geotiff_tag v="32767"/>
       <ellipsoid_epsg_code v="0"/>
    </Ellipsoid>
  • geodetic.xml
 <Datum datum_code="MARS2000_IAUSPHERE">
       <datum_name v="MARS2000_IAUSPHERE"/>
       <ellipsoid_code v="MS"/>`
       <reference_datum_code v ="MARS2000_IAUSPHERE"/>
       <diff_A v="0.0"/>
       <diff_F v="0.0"/>
       <offset x="0.0" y="0.0" z="0.0"/>
       <error_estimates x="0.0" y="0.0" z="0.0"/>
       <rotation x="0.0" y="0.0" z="0.0"/>
       <scale v="1.0"/>
       <datum_geotiff_tag v="32767"/>
       <datum_epsg_code v="0"/>
       <nitf_dag v=""/>
       <nitf_dcd v="ZYX"/>
    </Datum>
  • CoordinateSystems.xml
    <CoordSys cs_name="MARS Equirectangular">
       <cs_type value="3"/>
       <datum_code value="MARS2000_IAUSPHERE"/>
       <is_datum_editable value="false"/>
       <display_units_type value="8"/>
       <horiz_units value="0"/>
       <vertical_reference value="0"/>
       <vert_dist_units value="3"/>
       <map_projection map_projection_type="19">
          <projection_parameters name="FALSE_NORTHING_POS" value="0.000000"/>
          <projection_parameters name="FALSE_NORTHING_NEG" value="0.000000"/>
          <projection_parameters name="FALSE_EASTING_POS" value="00000.000000"/>
          <projection_parameters name="FALSE_EASTING_NEG" value="00000.000000"/>
          <projection_parameters name="MIDDLE_LATITUDE" value="0.000000"/>
          <projection_parameters name="CENTRAL_MERIDIAN" value="0.000000"/>
          <projection_parameters name="CENTRAL_SCALE_FACTOR" value="1.000000"/>
       </map_projection>
       <geotiff_tag value="32767"/>
       <epsg_code value="0"/>
    </CoordSys>
    <CoordSys cs_name="MARS South Pole">
       <cs_type value="3"/>
       <datum_code value="MARS2000_IAUSPHERE"/>
       <is_datum_editable value="false"/>
       <display_units_type value="8"/>
       <horiz_units value="0"/>
       <vertical_reference value="0"/>
       <vert_dist_units value="3"/>
       <map_projection map_projection_type="9">
          <projection_parameters name="FALSE_NORTHING_POS" value="0.000000"/>
          <projection_parameters name="FALSE_NORTHING_NEG" value="0.000000"/>
          <projection_parameters name="FALSE_EASTING_POS" value="00000.000000"/>
          <projection_parameters name="FALSE_EASTING_NEG" value="00000.000000"/>
          <projection_parameters name="CENTRAL_LATITUDE" value="-90.000000"/>
          <projection_parameters name="CENTRAL_MERIDIAN" value="0.000000"/>
          <projection_parameters name="CENTRAL_SCALE_FACTOR" value="1.000000"/>
       </map_projection>
       <geotiff_tag value="32767"/>
       <epsg_code value="0"/>
    </CoordSys>
    <CoordSys cs_name="MARS North Pole">
       <cs_type value="3"/>
       <datum_code value="MARS2000_IAUSPHERE"/>
       <is_datum_editable value="false"/>
       <display_units_type value="8"/>
       <horiz_units value="0"/>
       <vertical_reference value="0"/>
       <vert_dist_units value="3"/>
       <map_projection map_projection_type="9">
          <projection_parameters name="FALSE_NORTHING_POS" value="0.000000"/>
          <projection_parameters name="FALSE_NORTHING_NEG" value="0.000000"/>
          <projection_parameters name="FALSE_EASTING_POS" value="00000.000000"/>
          <projection_parameters name="FALSE_EASTING_NEG" value="00000.000000"/>
          <projection_parameters name="CENTRAL_LATITUDE" value="90.000000"/>
          <projection_parameters name="CENTRAL_MERIDIAN" value="0.000000"/>
          <projection_parameters name="CENTRAL_SCALE_FACTOR" value="1.000000"/>
       </map_projection>
       <geotiff_tag value="32767"/>
       <epsg_code value="0"/>
    </CoordSys>
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