PDS_VERSION_ID        = PDS3
RECORD_TYPE           = STREAM

OBJECT                = TEXT
   PUBLICATION_DATE    = 2016-03-04
   NOTE                = "Description of contents of BROWSE directory"
END_OBJECT            = TEXT
END

TER and MTRDR browse products are organized in the appropriate BROWSE 
directory tree by year and day of year, e.g. /2007/2007_013/, with 
subdirectories for each observation identified by the class type and target 
ID (e.g. /FRT00003E12/).

Three data files and one detached PDS label file describing the three files 
constitutes a single TER/MTRDR browse product set. The three data files are:
- The .IMG file which stores the browse image as a 3-band 8-bit raw binary PDS
image object.
- The .HDR file which stores ENVI Header information associated with the IMG 
file. This file is provided as a convenience to users of the ENVI software 
and allows the TER and MTRDR browse products to be loaded directly into 
ENVI. For the map projected (MTR) data products the ENVI header also 
includes a coordinate system string generated by the ESRI Projection Engine 
(PE) that allows the products to be loaded into a GIS environment.
- The .PNG file which stores the 3-band 8-bit browse image in Portable 
Network Graphics (PNG) format with an alpha transparency channel that 
corresponds to the non-scene edge pixels.

The spatial dimensions of each PNG and IMG file match the spatial dimensions 
of the source TER or MTRDR.

The detached PDS label describes the three data files and includes 
traceability information for the source TER/MTRDR spectral summary parameter 
data product. For projected (MTR) products image map projection information 
that applies to both the PNG and IMG file is included. The label also 
records the scaling between the source 32-bit TER/MTRDR summary parameter 
data values and the 8-bit browse image files.

There are up to four browse products containing data derived from the VNIR 
detector, and up to thirteen browse products containing data derived from 
the IR detector. A single browse product (TAN) includes data from both 
detectors. A TER/MTRDR product set with sensor type J ("joined") has 
associated browse products from both detectors for a total of 18 products. A 
detailed description of the TER/MTRDR browse products is provided in the 
CRISM Data Product SIS.

The file naming convention for the TER and MTRDR browse products is as 
follows.

(ClassType)(ObsID)_(Counter)_ BR(BrowseProductType)_(Filetype)(version).(Ext)
where:

Class Type =
  FRT (Full Resolution Targeted Observation)
  HRL (Half Resolution Long Targeted Observation)
  HRS (Half Resolution Short Targeted Observation)
  
ObsID = nnnnnnnn, Observation ID, unique for the whole CRISM mission, 
expressed as a hexadecimal number

Counter = nn, the ordinal counter carried through from the source EDR

BrowseProductType = TRU, VNA, FEM, FM2, FAL, IRA, MAF, HYD, PHY, PFM, PAL, 
HYS, ICE, IC2, CAR, CR2, CHL, or TAN

Filetype = "TER" or "MTR"

version = 0, 1,...,9, a, ..., z

Ext = PNG, HDR, IMG, LBL