PDS_VERSION_ID                    = PDS3
LABEL_REVISION_NOTE               = "Scott Murchie, 2023-03-01"

RECORD_TYPE                       = "STREAM"
INSTRUMENT_HOST_NAME              = "MARS RECONNAISSANCE ORBITER"
SPACECRAFT_ID                     = MRO
INSTRUMENT_NAME                   = "COMPACT RECONNAISSANCE IMAGING
                                     SPECTROMETER FOR MARS"
INSTRUMENT_ID                     = CRISM
TARGET_NAME                       = MARS
OBJECT                            = DATA_SET_MAP_PROJECTION
DATA_SET_ID                      = "MRO-M-CRISM-5-RDR-VNIRHYPERSPECTRAL-V1.0"
  OBJECT                          = DATA_SET_MAP_PROJECTION_INFO
    MAP_PROJECTION_TYPE           = "POLAR STEREOGRAPHIC"
    MAP_PROJECTION_DESC           = "CRISM VNIR hyperspectral imaging of Mars
      is mosaicked into 1964 non-overlapping tiles each containing multiple
      strips of mapping data. Their longitude width increases poleward to
      keep tiles approximately the same in area. The adopted projection
      convention is planetocentric, positive east, using the 2000 IAU prime
      meridian and pole of rotation. The projection varies in 5 degree bands
      using EQUIRECTANGULAR equatorward of 87.5 degrees latitude, and POLAR
      latitude bands, STEREOGRAPHIC poleward of 87.5 degrees latitude.
      Sampling is 654 pixels per degree.

      For the latitude bands projected polar stereographically, projection
      is centered on the north or south pole. Lines of longitude extend
      radially from the pole and parallels of latitude are concentric
      circles around the center. In the north, longitude 0 extends straight
      down from the center and Longitude 90 East extends to the right. In
      the south, longitude 0 extends straight up from the center, and
      longitude 90 East extends to the right. Thus in any given tile,
      north is at a variable orientation in LINE-SAMPLE space. The
      transformation from line and sample coordinates to planetocentric
      latitude and longitude is given by these equations.

      x = (SAMPLE - LINE_PROJECTION_OFFSET - 0.5)/MAP_RESOLUTION
      y = (LINE - SAMPLE_PROJECTION_OFFSET - 0.5)/MAP_RESOLUTION

      r = sqrt(x^2 + y^2)

      lon = atan2(x,y) * 180/pi
      lat = 90 - 2*atan(r*pi/360) * 180/pi (northern hemisphere)
      lat = -90 + 2*atan(r*pi/360) * 180/pi (southern hemisphere)

      where

      lat = latitude in degrees and
      lon = longitude in degrees.

      MAP_RESOLUTION = 654 pixels/degree.

      LINE_PROJECTION_OFFSET is the line number minus the line on which
      the map projection origin occurs. For a POLAR STEREOGRAPHIC
      projection the direction and magnitude of offset will depend on
      longitude of the map tile.

      SAMPLE_PROJECTION_OFFSET is the nearest sample number to the left of
      the projection longitude. For a POLAR STEREOGRAPHIC projection
      the direction and magnitude of offset will depend on
      longitude of the map tile.

      MAP_RESOLUTION is measured in pixels/degree.

      MAP_SCALE is measured in km/pixel and is an average.

      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       = "UNK"

    OBJECT                        = DS_MAP_PROJECTION_REF_INFO
      REFERENCE_KEY_ID            = "UNK"
    END_OBJECT                    = DS_MAP_PROJECTION_REF_INFO

  END_OBJECT                      = DATA_SET_MAP_PROJECTION_INFO
END_OBJECT                        = DATA_SET_MAP_PROJECTION

END