<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?xml-model href="https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1N00.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>
<?xml-model href="https://pds.nasa.gov/pds4/cart/v1/PDS4_CART_1N00_1970.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>
<?xml-model href="https://pds.nasa.gov/pds4/disp/v1/PDS4_DISP_1N00_1510.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>
<?xml-model href="https://pds.nasa.gov/pds4/geom/v1/PDS4_GEOM_1N00_1980.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>
<?xml-model href="https://pds.nasa.gov/pds4/msn/v1/PDS4_MSN_1N00_1310.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>

<Product_Observational xmlns="http://pds.nasa.gov/pds4/pds/v1" 
  xmlns:pds="http://pds.nasa.gov/pds4/pds/v1" 
  xmlns:cart="http://pds.nasa.gov/pds4/cart/v1" 
  xmlns:disp="http://pds.nasa.gov/pds4/disp/v1" 
  xmlns:geom="http://pds.nasa.gov/pds4/geom/v1"
  xmlns:msn="http://pds.nasa.gov/pds4/msn/v1"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation="http://pds.nasa.gov/pds4/pds/v1 https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1N00.xsd http://pds.nasa.gov/pds4/cart/v1 https://pds.nasa.gov/pds4/cart/v1/PDS4_CART_1N00_1970.xsd 
  http://pds.nasa.gov/pds4/disp/v1 https://pds.nasa.gov/pds4/disp/v1/PDS4_DISP_1N00_1510.xsd
  http://pds.nasa.gov/pds4/geom/v1 https://pds.nasa.gov/pds4/geom/v1/PDS4_GEOM_1N00_1980.xsd
  http://pds.nasa.gov/pds4/msn/v1 https://pds.nasa.gov/pds4/msn/v1/PDS4_MSN_1N00_1310.xsd">
  
  <Identification_Area>
    <logical_identifier>urn:nasa:pds:mgs_mola_topography_derived:data_meg032:megc90n000fb</logical_identifier>
    <version_id>1.0</version_id>
    <title>MGS MOLA MEGDR product: megc90n000fb</title>
    <information_model_version>1.23.0.0</information_model_version>
    <product_class>Product_Observational</product_class>
    <Citation_Information>
      <publication_year>2026</publication_year>
      <description>This data product accompanies the topographic and shape maps of Mars, at a resolution of 0.03125 (1/32) by 0.03125 degrees. It contains the number of observations per pixel that have been used to produce the data products.</description>
      <List_Author>
        <Person>
          <contributor_type>Producer</contributor_type>
          <given_name>David E.</given_name>
          <family_name>Smith</family_name>
          <Affiliation>
            <organization_name>Goddard Space Flight Center, MOLA Team</organization_name>
          </Affiliation>
        </Person>
        <Person>
          <contributor_type>DataCurator</contributor_type>
          <given_name>Madison N.</given_name>
          <family_name>Hughes</family_name>
          <Affiliation>
            <organization_name>Washington University in St. Louis</organization_name>
          </Affiliation>
        </Person>
      </List_Author>
    </Citation_Information>
    <Modification_History>
      <Modification_Detail>
        <modification_date>2026-08-25</modification_date>
        <version_id>1.0</version_id>
        <description>Initial PDS4 version</description>
      </Modification_Detail>
    </Modification_History>
  </Identification_Area>
  <Observation_Area>
    <Time_Coordinates>
      <start_date_time>1997-09-15T19:10:00.000Z</start_date_time>
      <stop_date_time>2001-06-30T11:10:40.000Z</stop_date_time>
    </Time_Coordinates>
    <Investigation_Area>
      <name>Mars Global Surveyor</name>
      <type>Mission</type>
      <Internal_Reference>
        <lid_reference>urn:nasa:pds:context:investigation:mission.mars_global_surveyor</lid_reference>
        <reference_type>data_to_investigation</reference_type>
      </Internal_Reference>
    </Investigation_Area>
    <Observing_System>
      <name>MOLA</name>
      <Observing_System_Component>
        <name>The Mars Global Surveyor Spacecraft</name>
        <type>Host</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument_host:spacecraft.mgs</lid_reference>
          <reference_type>is_instrument_host</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
      <Observing_System_Component>
        <name>Mars Global Surveyor Spacecraft Mars Orbiter Laser Altimeter</name>
        <type>Instrument</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument:mgs.mola</lid_reference>
          <reference_type>is_instrument</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
    </Observing_System>
    <Target_Identification>
      <name>Mars</name>
      <type>Planet</type>
      <Internal_Reference>
        <lid_reference>urn:nasa:pds:context:target:planet.mars</lid_reference>
        <reference_type>data_to_target</reference_type>
      </Internal_Reference>
    </Target_Identification>
    <Mission_Area>
      <msn:Mission_Information>
        <msn:Orbital_Mission>
          <msn:start_orbit_number>3</msn:start_orbit_number>
          <msn:stop_orbit_number>20333</msn:stop_orbit_number>
        </msn:Orbital_Mission>
      </msn:Mission_Information>
    </Mission_Area>
    <Discipline_Area>  
      <cart:Cartography>
        <Local_Internal_Reference>
          <local_identifier_reference>gridded_image</local_identifier_reference>
          <local_reference_type>cartography_parameters_to_image_object</local_reference_type>
        </Local_Internal_Reference>
        <cart:Spatial_Domain>
          <cart:Bounding_Coordinates>
            <cart:west_bounding_coordinate unit="deg">0</cart:west_bounding_coordinate>
            <cart:east_bounding_coordinate unit="deg">360</cart:east_bounding_coordinate>
            <cart:north_bounding_coordinate unit="deg">90</cart:north_bounding_coordinate>
            <cart:south_bounding_coordinate unit="deg">-90</cart:south_bounding_coordinate>
          </cart:Bounding_Coordinates>
        </cart:Spatial_Domain>
        <cart:Spatial_Reference_Information>
          <cart:Horizontal_Coordinate_System_Definition>
            <cart:Planar>
              <cart:Map_Projection>
                <cart:map_projection_name>Equirectangular</cart:map_projection_name>
                <cart:Equirectangular>
                  <cart:standard_parallel_1 unit="deg">0.</cart:standard_parallel_1>
                  <cart:longitude_of_central_meridian unit="deg">180.</cart:longitude_of_central_meridian>
                </cart:Equirectangular>
              </cart:Map_Projection>
              <cart:Planar_Coordinate_Information>
                <cart:planar_coordinate_encoding_method>Coordinate Pair</cart:planar_coordinate_encoding_method>
                <cart:Coordinate_Representation>
                  <cart:pixel_resolution_x unit="km/pixel">32</cart:pixel_resolution_x>
                  <cart:pixel_resolution_y unit="km/pixel">32</cart:pixel_resolution_y>
                  <cart:pixel_scale_x unit="pixel/deg">1.853</cart:pixel_scale_x>
                  <cart:pixel_scale_y unit="pixel/deg">1.853</cart:pixel_scale_y>
                </cart:Coordinate_Representation>
              </cart:Planar_Coordinate_Information>
              <cart:Geo_Transformation>
                <cart:upperleft_corner_x unit="m">-10673280</cart:upperleft_corner_x>
                <cart:upperleft_corner_y unit="m">5336640</cart:upperleft_corner_y>
              </cart:Geo_Transformation>
            </cart:Planar>
            <cart:Geodetic_Model>
              <cart:latitude_type>Planetocentric</cart:latitude_type>
              <cart:a_axis_radius unit="km">3396.0</cart:a_axis_radius>
              <cart:b_axis_radius unit="km">3396.0</cart:b_axis_radius>
              <cart:c_axis_radius unit="km">3396.0</cart:c_axis_radius>
              <cart:longitude_direction>Positive East</cart:longitude_direction>
              <cart:coordinate_system_type>Body-fixed Rotating</cart:coordinate_system_type>
              <cart:coordinate_system_name>PLANETOCENTRIC</cart:coordinate_system_name>
            </cart:Geodetic_Model>
          </cart:Horizontal_Coordinate_System_Definition>
        </cart:Spatial_Reference_Information>
      </cart:Cartography>
      <disp:Display_Settings>
        <Local_Internal_Reference>
          <local_identifier_reference>gridded_image</local_identifier_reference>
          <local_reference_type>display_settings_to_array</local_reference_type>
        </Local_Internal_Reference>
        <disp:Display_Direction>
          <disp:horizontal_display_axis>Sample</disp:horizontal_display_axis>
          <disp:horizontal_display_direction>Left to Right</disp:horizontal_display_direction>
          <disp:vertical_display_axis>Line</disp:vertical_display_axis>
          <disp:vertical_display_direction>Top to Bottom</disp:vertical_display_direction>
        </disp:Display_Direction>
      </disp:Display_Settings>
      <geom:Geometry>
        <geom:Geometry_Orbiter>
          <geom:geometry_reference_time_utc>1999-08-08T03:10:20.000Z</geom:geometry_reference_time_utc>
          <geom:geometry_start_time_utc>1997-09-15T19:10:00.000Z</geom:geometry_start_time_utc>
          <geom:geometry_stop_time_utc>2001-06-30T11:10:40.000Z</geom:geometry_stop_time_utc>
          <geom:Orbiter_Identification>
            <geom:Central_Body_Identification><geom:name>Mars</geom:name></geom:Central_Body_Identification>           
            <geom:Coordinate_System_Identification>
              <geom:coordinate_system_type>Planetocentric</geom:coordinate_system_type>
              <geom:Coordinate_System_Origin_Identification>
                <geom:name>Mars</geom:name>
              </geom:Coordinate_System_Origin_Identification>
              <geom:Reference_Frame_Identification>
                <geom:name>IAU2000_MARS</geom:name>
              </geom:Reference_Frame_Identification>
            </geom:Coordinate_System_Identification>
          </geom:Orbiter_Identification>
        </geom:Geometry_Orbiter>
      </geom:Geometry>
    </Discipline_Area>
  </Observation_Area>
  <Reference_List>
    <Internal_Reference>
      <lid_reference>urn:nasa:pds:mgs_mola_topography_derived:document:egdrsis</lid_reference>
      <reference_type>data_to_document</reference_type>
    </Internal_Reference>
    <Internal_Reference>
      <lid_reference>urn:nasa:pds:mgs_mola_topography_derived:document:mola_envi</lid_reference>
      <reference_type>data_to_document</reference_type>
    </Internal_Reference>
  </Reference_List>
  <File_Area_Observational>
    <File>
      <file_name>megc90n000fb.img</file_name>
      <creation_date_time>2003-04-11T01:00:00</creation_date_time>
      <comment>This data product accompanies the
 topographic and shape maps of Mars, at a resolution of 0.03125 (1/32)
 by 0.03125 degrees. It contains the number of observations per pixel
 that have been used to produce the data products. The map is in the form
 of a binary table with one row for each 0.03125-degree latitude. A
 total of approximately 600 million observations are represented.</comment>
    </File>
    <Array_2D_Image>
      <local_identifier>gridded_image</local_identifier>
      <offset unit="byte">0</offset>
      <axes>2</axes>
      <axis_index_order>Last Index Fastest</axis_index_order>
      <description>The number of observations, or counts, in a given latitude-longitude bin.</description>
      <Element_Array>
        <data_type>SignedMSB2</data_type>
      </Element_Array>
      <Axis_Array>
        <axis_name>Line</axis_name>
        <elements>5760</elements>
        <sequence_number>1</sequence_number>
      </Axis_Array>
      <Axis_Array>
        <axis_name>Sample</axis_name>
        <elements>11520</elements>
        <sequence_number>2</sequence_number>
      </Axis_Array>
    </Array_2D_Image>
  </File_Area_Observational>
  <File_Area_Observational_Supplemental>
    <File>
      <file_name>megc90n000fb.lbl</file_name>
    </File>
    <Stream_Text>
      <offset unit="byte">0</offset>
      <parsing_standard_id>PDS3</parsing_standard_id>
      <description>Original PDS3 label.</description>
      <record_delimiter>Carriage-Return Line-Feed</record_delimiter>
    </Stream_Text>
  </File_Area_Observational_Supplemental>
  <File_Area_Observational_Supplemental>
    <File>
      <file_name>megc90n000fb.hdr</file_name>
    </File>
    <Stream_Text>
      <offset unit="byte">0</offset>
      <parsing_standard_id>7-Bit ASCII Text</parsing_standard_id>
      <description> The ENVI header is a separate ASCII file that includes basic image data file characteristics. 
        ENVI will read both files and use the map projection information in the header file to correctly display
        the image. The header files are provided because ENVI is not able to import the map projection information 
        directly from the MEGDR image labels. 
      </description>
      <record_delimiter>Carriage-Return Line-Feed</record_delimiter>
    </Stream_Text>
  </File_Area_Observational_Supplemental>
</Product_Observational>

