PDS_VERSION_ID                = PDS3
RECORD_TYPE                   = STREAM
OBJECT                        = TEXT
  PUBLICATION_DATE            = 2000-02-02
  NOTE                        = "Description of the BROWSE
     directory contents."
END_OBJECT                    = TEXT
END


I.  Introduction

     Browse files are included for several of the data product types
in this collection.  Most of the browse products were derived from the
original CD-ROM volumes.  Descriptions of the browse products taken
from the original volumes are provided below.  Each volume in the
three volume set contains a complete set of the browse products except
for the MAG/ER products, which are large.  The MAG/ER browse products
are only contained on the second volume of this set, which is the
volume that also contains the MAG/ER archive data products.

     These browse products can be accessed directly or by using the
user interface found in the EXTRAS directory.


II. Accelerometer Browse Files

     The accelerometer browse products are GIF images showing plots of
spacecraft velocity change as a function of time.  These plots were
generated from the COUNTS.TAB files of the accelerometer data set.
Note that a smoothing function was applied to the original data in
making the browse products in order to reduced the quantization
effects in the data.

     There is one browse product for each orbit of accelerometer data.
Browse products are divided into subdirectories containing a group of
100 orbits.  The subdirectory names have the form PnnXX where nn is
the 2 most-significant digits of the orbit number.  The individual
browse products have file names of the form ACCnnnn.GIF where nnnn is
the 4-digit orbit number.


III. MAG/ER Browse Files

   The MAGER browse directories contain PostScript files representing
plots of the data.  There is a browse directory for each of the
original CD-ROM volumes.  The subdirectories are:

  RMS        Contains 3-panel plots of magnetic field magnitude and of
             RMS values of components BX and BY (in sensor coordinates).

  XYPLANE    Contains plots of XY-plane projections (in planetocentric
             coordinates) of spacecraft trajectory vectors and magnetic
             field vectors.

  XZPLANE    Contains plots of XZ-plane projections (in planetocentric
             coordinates) of spacecraft trajectory vectors and magnetic
             field vectors.

  YZPLANE    Contains plots of YZ-plane projections (in planetocentric
             coordinates) of spacecraft trajectory vectors and magnetic
             field vectors.


IV.  MOC Browse Files

     The MOC browse files are JPEG-format reduced resolution versions
of the original MOC images.  The browse images were taken from the
original CD-ROM volumes.  A HTML file is included with each MOC browse
image that will display a subset of the image label information.

     The MOC browse images are divided into subdirectories where each
subdirectory contains images from a group of ten orbits.  The
subdirectory and browse file naming conventions are similar to the
conventions used for the archive data products.


V. MOLA Browse Files

     The MOLA browse directory contains GIF images of topography
profiles generated from each of the MOLA PEDR data products.  The GIF
images may be displayed in a Web browser.

     The browse images are divided into subdirectories based on orbit
number.  For example, subdirectory AP002XX contains images from orbits
200-299.  Each browse image is a topography profile generated from the
PEDR data product.  MOLA browse image file names have the form
APnnnnnK.GIF, where nnnnn is the PEDR orbit number.
               

VI. Radio Science Browse Files

     The radio science browse products are GIF images showing plots of
atmosphere temperature and pressure as a function of height.  These
plots were generated from the temperature-pressure profiles (TPS) of
the radio science data set.

     There are two browse products for each TPS file: one for the
temperature profile and one for the pressure profile.  Radio Science
browse products are divided into two subdirectories based on the
original CD-ROM volume.  The subdirectory names have the form TPS_nnnn
where nnnn is taken from the original radio science reduced data set
CD-ROM volume_id.  File names for the browse products use the first
eight characters of the original data product name with a t or p
appended for the temperature or pressure profile, respectively.  The
files have the extension of GIF.