PDS_VERSION_ID        = PDS3
RECORD_TYPE           = STREAM

OBJECT                = TEXT
   PUBLICATION_DATE    = 2023-03-01
   NOTE                = "Description of contents of BROWSE directory"
END_OBJECT            = TEXT
END
 
VRDR browse products are organized into 30 subdirectories named by the Mars 
Chart containing the latitude and longitude of its upper left corner, e.g. 
MC01. Latitude and longitude limits of Mars Charts are given below. 

Identifer  Chart Name      Latitude Range     Longitude Range
MC01       Mare Boreum       60 to 90          -180 to 180
MC02       Diacria           30 to 60          -180 to -120
MC03       Arcadia           30 to 60          -120 to -60
MC04       Mare Acidalium    30 to 60           -60 to 0
MC05       Ismenius Lacus    30 to 60             0 to 60
MC06       Casius            30 to 60            60 to 120
MC07       Cebrenia          30 to 60            60 to 180
MC08       Amazonis           0 to 30          -180 to -135
MC09       Tharsis            0 to 30          -135 to -90
MC10       Lunae Palus        0 to 30           -90 to -45
MC11       Oxia Palus         0 to 30           -45 to 0
MC12       Arabia             0 to 30             0 to 45
MC13       Syrtis Major       0 to 30            45 to 90
MC14       Amenthes           0 to 30            90 to 135
MC15       Elysium            0 to 30           135 to 180
MC16       Memnonia           0 to -30         -180 to -135
MC17       Phoenicis Lacus    0 to -30         -135 to -90
MC18       Coprates           0 to -30          -90 to -45
MC19       Margaritifer Sinus 0 to -30          -45 to 0
MC20       Sinus Sabaeus      0 to -30            0 to 45
MC21       Iapygia            0 to -30           45 to 90
MC22       Mare Tyrrhenum     0 to -30           90 to 135
MC23       Aeolis             0 to -30          135 to 180
MC24       Phaethontis      -30 to -60         -180 to -120
MC25       Thaumasia        -30 to -60         -120 to -60
MC26       Argyre           -30 to -60          -60 to 0
MC27       Noachis          -30 to -60            0 to 60
MC28       Hellas           -30 to -60           60 to 120
MC29       Eridania         -30 to -60          120 to 180
MC30       Mare Australe    -60 to -90         -180 to 180

BROWSE PRODUCTS FOR VRDRs

       The VRDR browse product set consists of three data files and a 
       detached PDS label file. The label file contains the metadata and 
       pointers to the three data files. The three data files are 1) an IMG 
       file containing the browse product image as a three-band PDS IMAGE 
       object; 2) a PNG file containing the browse product image in the 
       Portable Network Graphics file format (three bands and an alpha 
       transparency channel); and 3) a HDR file associated with the IMG file 
       which stores file format (and map projection information) in 
       the ENVI header format. This allows users of the ENVI image 
       processing software to readily read in the image data. The 
       SOURCE_PRODUCT_ID keyword in the PDS label links the browse products 
       to the source MTRDR.  
       
       The following formulations are used.

          Abbreviation = TRU
          Name         = True color
          R Component  = R600
          G Component  = R530
          B Component  = R440
          Additional description: An enhanced natural color representation 
          of the scene composed of spectral channels across the visible 
          spectrum. Contrast greater than the human eye would see.

          Abbreviation = VNA
          Name = VNIR albedo
          R Component = R770
          G Component = R770
          B Component = R770
          Additional description: Reflectance at 770 nm as a proxy for VNIR 
          albedo and may be used to correlate spectral variations with 
          morphology. 

          Abbreviation = FEM
          Name = Fe Minerals
          R Component = BD530_2
          G Component = SH600_2
          B Component = BDI1000VIS
          Additional description: Mafic minerals appear blue, nanophase 
          ferric oxides red, and dust-coated mafic rocks or lithified 
          dust yellow/green.

          Abbreviation = FM2
          Name = Fe minerals, v2
          R Component = BD530_2
          G Component = BD920_2
          B Component = BDI1000VIS
          Additional description: Mafic minerals appear blue, crystalline
          hematite green or yellow, and nanophase ferric oxides red.