PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2001-12-20 NOTE = "EXTRINFO.TXT describes the files in the EXTRAS directory of this disk." END_OBJECT = TEXT END INTRODUCTION The EXTRAS directory contains files which facilitate the use of the data on the disk, but which are not actually required for the use or understanding of those data. The main files in the EXTRAS directory are HTML documents which can be viewed with a Web browser and used to navigate the disk via links. The directory also contains images in GIF and JPEG formats for display within the HTML pages. Note that each logical volume on this disk also has an EXTRAS directory of its own. These directories are not described by the present document; please see the EXTRINFO.TXT file on each volume for further information. IMAGE CREDITS The image files in EXTRAS are borrowed, with or without modification, from the Mars Global Surveyor Pre-Mapping Phase Pilot DVD Archive, Volume 1, Version 1 (MGS_1001). The main topographic map (here called MAP.GIF) has been substantially modified from the original image. The PDS Geosciences Node is hereby acknowledged as the source of the original borrowed images. TOP-LEVEL FILES IN EXTRAS MAP.HTM - an HTML document for display of a full topographic map of Mars MAP.GIF - the topographic map of Mars, as a GIF image FACEPLTE.AI - (These files are for internal PDS use. They do not BACKLINR.AI - serve any purpose for the user of the disk.) SUBDIRECTORIES OF EXTRAS 30DEGSQR - contains JPEG images of 30 x 30 deg map squares, together with HTML for display of those images 5DEGSQR - contains HTML documents linking to data files associated with particular 5 x 5 deg map squares. These files are organized into subdirectories, one for each 5 deg of latitude. FILE NAMING CONVENTIONS The JPEG and HTML files associated with a given map square have the names AAAABBBB.CCC, where: AAAA is the latitude of the lower left corner of the square, with 'N' taking the place of any minus sign; BBBB is the longitude of the lower left corner of the square, with 'N' taking the place of any minus sign; CCC is the file extension 'JPG' or 'HTM', according to file type. Under the 5DEGSQR directory, the subdirectory AAAA contains files associated with latitude AAAA, where AAAA is a number with any minus sign replaced by 'N'. NOTES ON THE USE OF THE MAP INTERFACE The main topographic map of Mars contains dotted curves representing the ground tracks of the spacecraft under 200 km altitude. The tracks are color coded, with red, blue, white and gray corresponding to the AB-1, SPO-1, SPO-2 and AB-2/TTM mission subphases, respectively. On the main map, each 30 x 30 deg map square can be clicked to reveal a more detailed map of that square. On this 30 x 30 deg map, each 5 x 5 deg square can be clicked to reveal a table of data files, with clickable links to the files present on this DVD. The colored dots and lines on the 30 x 30 deg maps are features of the original images from PDS Geosciences, and are not of direct use in this interface. The coordinates displayed on the 30 x 30 deg maps are defined differently from those on the main map. Because of inherent technical limitations, the clickable areas on the maps may be offset by a few pixels from the map areas to which they correspond. Users who wish to determine exactly which data files pertain to which regions should inspect the data files themselves rather than relying solely upon the maps. If you find an error in this map interface, please report it to the PPI Node of the PDS. The error reporting procedure is described in the AAREADME.TXT file under each logical volume on this DVD.