CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL
RECORD_TYPE                    = STREAM
PRODUCT_CREATION_TIME          = 1993-07-27
OBJECT                         = TEXT
  NOTE                         = "Special image file description."
END_OBJECT                     = TEXT
END    
  
           Syrtis Major Hemisphere - Orthographic Projection
           -------------------------------------------------

The image files contained in the SPECIAL/347SO sub-directory are global
mosaics of the Syrtis Major Hemisphere of Mars. The original images were
acquired during orbit 1,347 of Viking 1 on March 6, 1980. 

The images were acquired during early northern summer on Mars
(aerocentric solar longitude = 75 degrees). The center of this image is
near latitude 7 degrees, longitude 315 degrees, and the limits of this
mosaic are approximately latitude -60 degrees to 60 degrees and
longitude 260 degrees to 350 degrees. 

The images are in an orthographic projection with scales of 1/4
Degree/Pixel (14.8 KM/Pixel, MC* files), 1/8 Degree/Pixel (7.40
KM/Pixel, MD* files), 1/16 Degree/Pixel (3.70 KM/Pixel, ME* files), 1/32
Degree/Pixel (1.85 KM/Pixel, MF* files), and 1/64 Degree/Pixel (.925
KM/Pixel, MG* files). The MG* files contain selected sub-areas of the 
mosaic.

The large circular area with a bright yellow color (in this rendition) 
located in the upper left area of the image is known as Arabia. The
boundary between the ancient, heavily-cratered southern highlands and
the younger northern plains occurs far to the north (latitude 40
degrees) on this side of the planet, just north of Arabia. The dark blue
area to the right of Arabia, called Syrtis Major Planum, is a low-relief
volcanic shield of probable basaltic composition. The bright yellow area
to the right of Syrtis Major is Isidis Planitia, an ancient impact
basin. Bright white areas to the south, including the Hellas impact
basin at lower right, are covered by carbon dioxide frost. 

Image Processing by Jody Swann/Tammy Becker/Alfred McEwen, using the
PICS (Planetary Image Cartography System) image processing system
developed at the U.S. Geological Survey in Flagstaff, Arizona.