PDS_VERSION_ID      = PDS3
RECORD_TYPE         = STREAM
OBJECT              = TEXT
  PUBLICATION_DATE    = 2016-09-01
  NOTE                = "Description of contents of EXTRAS directory"
END_OBJECT          = TEXT
END

The EXTRAS directory of a PDS archive contains supplementary material that
may be of interest to users of the archive, but that is not essential to 
the understanding of the data.

In the MRO Derived Gravity archive, the EXTRAS directory contains JPEG 
images of the maps in the DATA/RSDMAP directory, which may be useful for 
quick viewing of the products. The JPEG versions are not suitable for 
data analysis.

Also in this EXTRAS directory, the CLONES subdirectory contains an ensemble 
of 500 "clone" models that are samples drawn from the error distribution of 
the Mars gravity model GMM-3 produced by NASA/GSFC. These clone models may 
be useful for modeling studies and obviate the need to sample the full error 
covariance matrix directly. More information is in CLONEINFO.TXT.