Data Set Overview
  =================
    The THEMIS IR-PBT data set contains the spatially registered, infrared
    brightness temperature images derived from the projected radiance
    (IR-GEO) products.  Each image header includes basic parameters
    describing the observation and image specific details of processing.

    The IR-PBT data set is one of several associated data sets included on
    the Mars Odyssey THEMIS Projected Products volume.  These data sets
    are derived from THEMIS calibrated radiance products (RDR) and include
    the spatially registered, radiance products and various other derived
    products.  One or more map projections of each radiance product is
    provided in the GEO data set, with each projection stored in a single
    ISIS-3 CUBE image file and associated with a detached PDS ASCII label.
    Derived (PBT and ALB) data sets are stored with each observation in a
    standard PDS IMAGE file.


  Modification History
  ====================
    Version 1 data volumes that include the IR-PBT data set are
    ODTGEO_10001 through ODTGEO_10047, released between Jan 2003 and
    April 2014. The release of Version 2 data volumes began in July 2014,
    with the re-release of previously released volumes following shortly
    thereafter.

    Version 2 supersedes version 1 and was necessitated by significant
    improvements to the ISIS software used to generate all THEMIS projected
    products.  This includes, but is not limited to, a new THEMIS IR
    camera model which improves the band-to-band registration of projected
    products.  Additional details are discussed in the ERRATA.TXT file
    available on the volume with this data set.


  Data
  ====
    The THEMIS instrument is a combined thermal infrared (IR) and visible
    (VIS) multispectral, pushbroom imager.  The IR and VIS detector arrays
    are co-aligned, allowing, if desired, the simultaneous observation of the
    same Mars surface location with each detector.  The Mars Odyssey THEMIS
    Standard Products volume includes the calibrated data sets (IR-RDR and
    VIS-RDR); however, these products are not spatially registered and bands
    within a single image can be offset by as much as 10 lines and/or
    columns.

    The cartographic conversion of the THEMIS observations using the ISIS-3
    software results in one projection per each multispectral ISIS-3 CUBE
    file.  A standard ISIS-3 CUBE includes a binary image, an ASCII header
    label, header data tables (optional), and an ASCII footer listing the
    file processing history.  A detached, ASCII label is associated with
    each THEMIS GEO product, duplicating the information attached to the
    image data, and conforming to PDS standard formats.

    In addition to the projection, the generation of the THEMIS GEO products
    includes multiple processing steps which may invalidate the calibrated
    radiance values inherited from the source RDR product.  The IR-GEO
    products are atmospherically corrected calibrated radiance, making them
    ideal for use in spectroscopic surface studies.  A single band, usually
    band 9 (12.57 um), is further processed to generate the IR-PBT single
    band, PDS IMAGE files.  The VIS-GEO products are cosmetically filtered
    after projection, making them ideal for use with other projected Mars
    imagery data sets.  The projected visible albedo product (VIS-ALB) is
    generated from a single band of the VIS-RDR, usually band 3 (0.654 um),
    and the resulting albedo values compare favorably with albedo
    measurements from the Mars Global Surveyor TES instrument.

    For more details of the THEMIS geometric processing algorithms and the
    data product formats, please refer to the Mars Odyssey THEMIS: Geometric
    Processing User's Guide (CHRISTENSEN2014b) included with this data set
    archive.


  Coordinate System
  =================
    All projected products on this volume are generated using the
    appropriate Odyssey SPICE kernels and a THEMIS specific model in
    the ISIS software.  All projections are based on the Mars IAU 2000
    aerocentric model with east positive longitude.  Image specific
    map projection details are stored in the label of each image file.


  Software
  ========
    The GEO data products on this volume are ISIS-3 standard CUBE files.
    ISIS is an image processing package produced by USGS-Flagstaff and
    available at http://isis.astrogeology.usgs.gov.

    The PBT and ALB data products on this volume follow the standards for
    the PDS IMAGE file structure.  Any software tool that understands that
    structure should be able to open and manipulate them.

    The THEMIS team uses the software tool DAVINCI to display and analyze
    all the data products.  DAVINCI is a data analysis package for working
    with multi-spectral and PDS standard images; it is distributed by the
    ASU Mars Space Flight Facility and is available at
    http://davinci.asu.edu.


  Media/Format
  ============
    The publication and distribution of this data set will be facilitated
    online through the THEMIS Data Node (http://static.mars.asu.edu/pds).
    Due to the large volume of data products expected from the mission,
    physical copies of the data will be made for PDS long-term archive
    purposes only.

Please refer to the Mars Odyssey THEMIS: Geometric Processing User's
    Guide (CHRISTENSEN2014b), which is included with this data set archive.