PDS_VERSION_ID     = PDS3
RECORD_TYPE        = STREAM
OBJECT             = TEXT
  PUBLICATION_DATE = 1999-12-06
  NOTE             = "Description of SPLITORB software provided 
    with the MGS MOLA archive volumes"
END_OBJECT         = TEXT
END

FILES IN THIS DIRECTORY
-----------------------

SPLTINFO.TXT - The file you are reading.

SPLITORB.PRO - IDL script to separate MOLA PEDR files into 
               individual orbits


SPLITORB SOFTWARE FOR MGS MOLA ARCHIVE VOLUMES
-----------------------------------------------

SPLITORB is a script written in IDL to read a MOLA PEDR data file
containing data from several orbits, and generate from it a set of files
each containing data from one orbit. To use this script, the user must
already have IDL installed.  IDL is commercial software produced by
Research Systems, 2995 Wilderness Place, Boulder, Colorado 80301, phone
303-786-9900, email info@rsinc.com. The Research Systems World-Wide Web
site is http://www.rsinc.com.

At the beginning of the Mapping Phase of the MGS mission, PEDRs began to
be aggregated by day instead of by orbit as they had been in the Cruise
and Orbit Insertion phases. Thus one Mapping Phase PEDR contains data
from a variable number of orbits.  

SPLITORB is intended to accompany the IDL script MPROF, also included
on this volume. MPROF was written to operate on PEDR files that contain
only one orbit's worth of data. A Mapping Phase PEDR must first be
broken down into separate orbits with SPLITORB before MPROF can be used
to plot the data.

SPLITORB works by reading each PEDR record, looking for the orbit
number field, and writing the record to an output file.  The procedure
will append the record to the output file for that orbit, if one already
exists, or start a new file for that orbit. The user should make sure
that input and output files are in different directories, or SPLITORB
may try to append records to an input file.  SPLITORB modifies the
attached PDS label to make it valid for the single-orbit file.

Inputs:

INPUT_FILE -- The full path of the multiple-orbit MOLA PEDR input file.

OUTPUT_DIRECTORY -- The full path of the directory in which the
procedure will write single-orbit PEDR files.  End the path with the
appropriate character for your operating system.  
Example on a PC: 'C:\temp\pedrs\single\' 
Example on a UNIX computer: '/home/user/pedrs/single/'

VERBOSE -- (Optional) Set this keyword to have the procedure display its
progress in the standard log window as it executes.

LOWERCASE -- (Optional) Set this keyword to force the output file name
to lower case letters.  Otherwise, the output file name will have the
case indicated in the header of the input file.  This keyword is
superceded by the UPPERCASE keyword.

UPPERCASE -- (Optional) Set this keyword to force the output file name
to upper case letters.  Otherwise, the output file name will have the
case indicated in the header of the input file.  This keyword supercedes
the LOWERCASE keyword.

Examples:

splitorb, '/data/pedr/ap10942g.b', '/output/'
splitorb, '/data/pedr/ap11015g.b', '/output/', /verbose, /lowercase

SPLITORB was adapted from a program called SPLITPEDR written in C for
Sun/UNIX systems by C. David Brown, Washington University, St.  Louis,
Missouri, email dbrown@geoid.wustl.edu. It was written in IDL for this
PDS archive volume by Judd Bowman, PDS Geosciences Node, Washington
University, St. Louis, Missouri, geosci@wunder.wustl.edu.