PDS_VERSION_ID        = PDS3
RECORD_TYPE           = STREAM
OBJECT                = TEXT
  PUBLICATION_DATE      = 2016-11-08
  NOTE                  = "
    Description of the contents of the SAMPLES directory

###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################

  "
END_OBJECT            = TEXT

END

This file describes the DOCUMENT/SAMPLES/ sub-directory of this New 
Horizons LORRI instrument dataset.  

The purpose of this SAMPLES/ sub-directory is to hold files that have, in
ASCII form, a subset of the contents of a sampling of binary data files,
specifically FITS Primary Data Units (PDUs) and Extension Data Units
(EDUs).

The data sampled ensure that one ASCII sample set of each available unique 
combination of three-letter prefix, ApID (or APID; Application Process ID),
and CODMAC level (Raw or Calibrated) within each data set is present in that
data set for a given instrument.

A copy of the source FITS file for each ASCII sample is also available in
this same SAMPLES/ sub-directory.  Note that although this source FITS file
was generated via the New Horizons data pipeline, has a format logically
analogous to similar data files in this data set, and may even have
identical values to a FITS file in this or any other data set, the physical
copy in this directory was never intended to be archived AS MISSION DATA,
and all mission-related quantities in the PDS label (e.g. DATA_SET_ID,
PRODUCT_ID, etc.) ARE ARTIFICIAL in the context of this SAMPLES/ sub-
directory.  This does not affect the purpose of the FITS file in this
directory because the only purpose of the FITS file here is, in combination
with the corresponding ASCII windows, to provide a Rosetta Stone for the
data user to validate their methodology of reading the binary FITS data.
Note to PDS validators:  this means that DATA_SET_IDs may exist in PDS
labels in this sub-directory which will raise referential integrity
exceptions in data set validation tools; those exceptions may be advisedly
ignored.

###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################
### N.B. THE FILES IN THIS DIRECTORY ARE SAMPLES INTENDED ***ONLY***    ###
###      TO SUPPORT USERS TRYING TO CONFIRM THEY ARE DECODING AND       ###
###      INTERPRETING THE DATA CORRECTLY; THESE FILES ARE ***NOT***     ###
###      INTENDED FOR SCIENTIFIC DATA ANALYSIS!                         ###
###      SPECIFICALLY, THE DATA_SET_ID VALUES IN THE PDS LABELS FOR THE ###
###      FITS FILES ARE SYNTACTICALLY VALID BUT OTHERWISE ARTIFICIAL.   ###
###########################################################################

As noted below, the user may refer to the PRODUCT_ID and the VOLUME_ID 
in the ASCII sample to locate the binary data file in its original
location. 

/DOCUMENT/ Top-level Directory containing supplemental documentation
  |         for LORRI data.
  |
  +-/SAMPLES/   Sub-directory with data samples; one such sample shown here
      |
      +- LORRI_SAMPLES.LBL          PDS label for sample files
      |
      +- XXX_0123456789_0AB_E_1_00.ASC    Sample data file for PDU (_00) of
      |                                     Raw (_e_ => _eng_) data file.  
      |
      +- XXX_0123456789_0AB_S_1_02.ASC    Sample data file for 2nd (_02) EDU 
      |                                     of Calibrated (_s_ => _sci_) 
      |                                     data file.  
      |
      +- XXX_0123456789_0AB_E_1_00.FIT    Source FITS file
      +- XXX_0123456789_0AB_E_1_00.LBL    PDS label for source FITS file

The sample file naming convention is a modified version of the data set
Filename and Product ID convention (see AAREADME.TXT for more details 
of the data set convention).

"XXX" is a three-letter prefix dependent on the instrument and/or 
observation parameters (e.g. filter, if applicable). 

At its core, the sample file name convention is the same as the data set 
convention with the extension number added.  However, in order to stay 
within PDS filename length restrictions, each sample file name has had 
two of its corresponding data file's filename components shortened.

Specifically:

1) Removed 0X prefix before ApID

The application ID (e.g. 0X7B0) component has had the 0X prefix removed.
This prefix indicates that the ApID is hexadecimal and is superfluous
because all ApIDs in the filenames and product IDs are hexadecimal.  


2) Shortened ENG & SCI components.

The _ENG_ & _SCI_ components, which indicate Raw and Calibrated data,
have been shortened to _E_ and _S_, respectively. 


3) Added extension number.

Each sample file corresponds to one data object in a data file.  In FITS
jargon, the data objects are either the Primary Data Unit (PDU) or one of 
the Extension Data Units (EDUs).  Sample files containing ASCII versions 
of a PDU will have a suffix of "_00" before the .ASC final suffix.  Sample
files containing ASCII version of EDUs will have a suffix "_NN" with the 
Extension number, where the Extension number of the first EDU after the 
PDU is EDU 1.  


For example, the files associated with Product ID 

  XXX_0123456789_0X7B0_ENG_1 

will become

  XXX_0123456789_7B0_E_1_NN.ASC

via the following steps:

  XXX_0123456789_0X7B0_ENG_1
  |              | /           1) Remove 0X prefix before ApID 0X07B0
  XXX_0123456789_7B0_ENG_1
  |                   |/       2) Shorten ENG to E
  XXX_0123456789_7B0_E_1
  |                     |\     3) Add extension numbers and .ASC suffix
  |                     | \
  XXX_0123456789_7B0_E_1_NN.ASC

Also, the Product ID, the data set path, and the generic volume ID are
included in the .ASC file as described in the document label.  

If all else fails, the user will be able to search for the data product
by inverting the steps above (truncate before _NN.ASC; expand _E_ or _S_
to _ENG_ or _SCI_, respectively; insert 0X before ApID characters i.e. 
after the second underscore) to reconstruct the Product ID, and use that 
Product ID to look up the data file in the index table.  

