PDS_VERSION_ID                    = PDS3
LABEL_REVISION_NOTE               = "
  2013-05-13 MESS:mauceri, Draft for peer review;
  2014-09-23 GEO:ward, Filled in UNK field;
  2016-02-08 MESS:mauceri, updated map resolution value."
RECORD_TYPE                       = "STREAM"
INSTRUMENT_HOST_NAME              = "MESSENGER"
INSTRUMENT_NAME                   = {"MERCURY ATMOSPHERIC AND SURFACE
                                     COMPOSITION SPECTROMETER"}
INSTRUMENT_ID                     = "MASCS"
DETECTOR_ID                       = "VIRS"
TARGET_NAME                       = MERCURY
OBJECT                            = DATA_SET_MAP_PROJECTION
DATA_SET_ID                       = "MESS-E/V/H-MASCS-5-VIRS-DAP-V1.0"
  OBJECT                          = DATA_SET_MAP_PROJECTION_INFO
    MAP_PROJECTION_TYPE           = "EQUIRECTANGULAR"
    MAP_PROJECTION_DESC           = "MASCS/VIRS images are global maps
      of Mercury. The adopted projection convention is planetocentric,
      positive east, using the MESSENGER-derived prime meridian and 
      other coordinate system values as defined in 
      pck00010_msgr_v21.tpc. The projection used is EQUIRECTANGULAR.

      The transformation from latitude and longitude to line
      and sample is given by the following equations:

      LINE = int(LINE_PROJECTION_OFFSET - lat*MAP_RESOLUTION)
      SAMPLE = int(SAMPLE_PROJECTION_OFFSET - lon*MAP_RESOLUTION)

      where lat = latitude and lon = longitude.

      Note that integral values of line and sample correspond to the 
      center of a pixel. Lat and lon are the latitude and longitude of 
      a given location on the surface, east positive.

      MAP_RESOLUTION = the map resolution in pixels per degree,
      85.15 pixels/degree for a DAP.

      LINE_PROJECTION_OFFSET = the line offset value of the map
      projection origin from the line and sample 1,1 (line and sample
      1,1 is considered the upper left corner of the digital array).
      For an EQUIRECTANGULAR map projection, origin is the equatorward
      edge of the map. The value of LINE_PROJECTION_OFFSET is
      positive for images starting north of the equator and is negative
      for images starting south of the equator.

      SAMPLE_PROJECTION_OFFSET = the sample offset value of the map
      projection origin from line and sample 1,1 (line and sample 1,1
      is considered the upper left corner of the digital array).
      For an EQUIRECTANGULAR map projection, the value of
      SAMPLE_PROJECTION_OFFSET is positive for images starting to the
      west of the projection longitude and is negative for images
      starting to the east of the projection longitude.

      MAP_RESOLUTION is measured in pixels/degree.

      MAP_SCALE is measured in m/pixel.

      There are four PDS parameters that specify the latitude and
      longitude boundaries of an image. MAXIMUM_LATITUDE and
      MINIMUM_LATITUDE specify the latitude boundaries of the image,
      and EASTERNMOST_LONGITUDE and WESTERNMOST_LONGITUDE specify
      the longitudinal boundaries of the map.

      Definitions of other mapping parameters can be found in the
      PDS Data Dictionary."

    ROTATIONAL_ELEMENT_DESC       = "See [SEIDELMANNETAL2002]."

    OBJECT                        = DS_MAP_PROJECTION_REF_INFO
      REFERENCE_KEY_ID            = "SEIDELMANNETAL2002"
    END_OBJECT                    = DS_MAP_PROJECTION_REF_INFO
    
    OBJECT                        = DS_MAP_PROJECTION_REF_INFO
      REFERENCE_KEY_ID            = "SNYDER1987"
    END_OBJECT                    = DS_MAP_PROJECTION_REF_INFO

  END_OBJECT                      = DATA_SET_MAP_PROJECTION_INFO
END_OBJECT                        = DATA_SET_MAP_PROJECTION

END