PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM INSTRUMENT_HOST_NAME = "2001 MARS ODYSSEY" INSTRUMENT_NAME = "GAMMA RAY SPECTROMETER" TARGET_NAME = MARS OBJECT = TEXT PUBLICATION_DATE = 2003-10-30 NOTE = "Introduction to Odyssey GRS SGS Data" END_OBJECT = TEXT END 2001 MARS ODYSSEY GAMMA RAY SPECTROMETER SUMMED GAMMA SPECTRA Introduction ------------ The Odyssey Gamma Ray Spectrometer (GRS) Summed Gamma Spectra (SGS) data products are spectra from the Gamma Sensor Head summed as counts and binned into 5x5 degree latitude/longitude bins and 15 degree Ls bins. These products are generated by processing GRS corrected gamma spectra (CGS). Information about the SGS product can be found in the GRS Intermediate Data Record Software Interface Specification (SIS) in the DOCUMENT directory of this archive. Information about the processing applied to these products can be found in the Gamma Processing document in the same directory. File Formats ------------ The GRS SGS data products are stored as binary files with detached ASCII-text PDS labels. Each file contains sums of spectra acquired over a 5 x 5 degree bins of latitude and longitude, and over 15 degrees of Ls. Data and label files are grouped into directories for each 15 degrees of Ls. File names for GRS SGS data files have the form of SGS_yy_nnn_mmm_xx.DAT, where yy indicates the Mars year of the Odyssey Mission starting with 01, nnn is the starting Ls, mmm is the ending Ls, and xx is a number for the latitude band. Latitude band numbers begin with 00 for the northernmost band and end with 35 for the southernmost band. An example file name is SGS_01_015_030_00.DAT. Each data file is described by a PDS label in a separate file with the same name, extension ".LBL", in the same directory as the data file. The labels contain identification and observation parameters associated with the data files and definitions for the TABLE object. The PDS labels include a pointer to a format file that contains column definitions (extension ".FMT"). The format file is found in the LABEL directory. Volume Contents --------------- The GRS SGS archive volume includes the following files and directories. Root directory AAREADME.TXT - the file you are reading ERRATA.TXT - notes and errata, if any VOLDESC.CAT - volume description for the PDS catalog INDEX directory INDXINFO.TXT - description of contents of this directory INDEX.TAB - index of all products in the archive INDEX.LBL - PDS label that describes INDEX.TAB DOCUMENT directory BAD_CODE.TXT - quality flag definitions DOCINFO.TXT - description of contents of this directory GRS-IDR-SIS.PDF - Detailed data product description in PDF format GRS-IDR-SIS.LBL - PDS label for GRS-IDR-SIS.PDF GRS_GAMMA_PROCESSING.PDF - Description of processing applied to SGS products GRS_GAMMA_PROCESSING.LBL - PDS label for GRS_GAMMA_PROCESSING.PDF TIME_CONVERSION_TABLES.PDF - Tables for converting Earth to Mars time TIME_CONVERSION_TABLES.LBL - PDS label for TIME_CONVERSION_TABLES.PDF CATALOG directory CATINFO.TXT - description of contents of this directory *.CAT - descriptions of dataset, instrument, spacecraft, mission, and personnel for the PDS catalog LABEL directory LABINFO.TXT - description of contents of this directory SUMMED_GAMMA_SPECTRA_COLS.FMT - format of columns in SGS data file SOFTWARE directory GRS_CODE.ZIP - library of Java source code to parse SGS data files GRS_CODE.LBL - PDS label for GRS_CODE.ZIP GRS_CODE_DOC.ZIP - documentation for Java code GRS_CODE_DOC.LBL - PDS label for GRS_CODE_DOC.ZIP SOFTINFO.TXT - description of contents of this directory Data directories Data files are aggregated by latitude. Each data file represents one 5 degree latitude band and contains 72 records, one record for each 5 degree longitude bin within the band of latitude. Thirty-six data files that represent the 36 5-degree latitude bands on the planet are grouped together in one subdirectory. The data in one subdirectory were acquired during a time interval of 15 degrees of solar longitude (Ls). The subdirectory names have the format YRyy_LSnnn_mmm, where yy is the Odyssey Mission Mars year, nnn is the starting Ls, and mmm is the ending Ls. These subdirectories are in turn grouped into top-level directories by Odyssey Mission Mars year, with names in the format YRyy. Contacts -------- For questions concerning these data products and documentation, contact: PDS Geosciences Node Washington University Dept. of Earth and Planetary Sciences 1 Brookings Drive St. Louis, MO 63130 314-935-5493 WWW Site: http://pds-geosciences.wustl.edu/ Electronic mail address: geosci@wunder.wustl.edu