===============================================================================
AVIRIS-3 Distribution Document 
===============================================================================

Michael Eastwood, meastwood@jpl.nasa.gov 
Sarah R. Lundeen, Sarah.R.Lundeen@jpl.nasa.gov
Robert O. Green, Robert.O.Green@jpl.nasa.gov
David R. Thompson, David.R.Thompson@jpl.nasa.gov 
John W. Chapman, John.W.Chapman@jpl.nasa.gov
Adam M. Chlus, Adam.M.Chlus@jpl.nasa.gov


This document describes the AVIRIS-3 L1 and L2 data 
products.  AVIRIS-3 is an imaging spectrometer that measures reflected 
radiance at 7.5nm intervals in the Visible to Shortwave Infrared (VSWIR) 
spectral range from 390-2510nm.  


-------------------------------------------------------------------------------
OVERVIEW
-------------------------------------------------------------------------------

Each flightline uses a specific base filename prefix: AV3YYYYMMDDtHHNNSS

YYYY:  The year of the airborne flight run.
MM:    The month of the airborne flight run (i.e. 05 represents May).
DD:    The day of the airborne flight run (22 is the 22nd day of the month)
HH:    UTC hour at the start of acquisition
NN:    UTC minute at the start of acquisition
SS:    UTC second at the start of acquisition

Each flightline name also includes a software processing version/tag and a parameter hash: VVV_PPPPPPPP

VVV:      Tag/version of product generation executable (PGE) used to generate data product.
PPPPPPPP:  Unique 8-digit truncated SHA-256 hash generated using input parameters and files.

The AVIRIS-3 data products for a particular airborne flight run are organized in the following directory structure:

/YYYYMMDDtHHNNSS_VVV
|   AV3YYYYMMDDtHHNNSS_L1B_RDN_VVV_PPPPPPPP_RDN_ORT
|   AV3YYYYMMDDtHHNNSS_L1B_RDN_VVV_PPPPPPPP_RDN_ORT.hdr
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_GLT
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_GLT.hdr
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_IGM
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_IGM.hdr
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_LOC_ORT
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_LOC_ORT.hdr
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_OBS_ORT
|   AV3YYYYMMDDtHHNNSS_L1B_ORT_VVV_PPPPPPPP_OBS_ORT.hdr
|   AV3YYYYMMDDtHHNNSS_L2A_OE_VVV_PPPPPPPP_RFL_ORT
|   AV3YYYYMMDDtHHNNSS_L2A_OE_VVV_PPPPPPPP_RFL_ORT.hdr
|   AV3YYYYMMDDtHHNNSS_L2A_OE_VVV_PPPPPPPP_UNC_ORT
|   AV3YYYYMMDDtHHNNSS_L2A_OE_VVV_PPPPPPPP_UNC_ORT.hdr

The file product codes signify:

   *OBS_ORT                          parameters relating to the geometry of observation and
                                     illumination rendered using the *_ort_glt lookup table.
   *OBS_ORT.hdr                      obs_ort image header file.
   *GLT                              geometric look-up table.
   *GLT.hdr                          GLT image header file.
   *IGM                              input geometry file.
   *IGM.hdr                          IGM image header file.
   *RDN_ORT          orthocorrected radiance image file.
   *RDN_ORT.hdr      radiance image header file.
   *RFL_ORT          orthocorrected reflectance image file.
   *RFL_ORT.hdr      reflectance image header file.
   *UNC_ORT          orthocorrected reflectance uncertainty image file.
   *UNC_ORT.hdr      uncertainty image header file.



------------------------------------------------------------------------------
FILE DESCRIPTIONS
------------------------------------------------------------------------------

*GLT   GEOMETRIC LOOKUP TABLE (GLT)

Contents:  Orthocorrected product with a fixed pixel size projected into a 
           rotated UTM system that contains the information about which 
           original pixel occupies which output pixel in the final product. 
           Additionally, each pixel is sign-coded to indicate if it is real 
           (indicated by a positive value) or a nearest-neighbor infill 
           (indicated by negative values).
           
           The GLT file contains two parameters:
              1) sample number
              2) original line number
              
File type: BINARY 16-bit, integer, IEEE.

Format:    Band interleaved by line

------------------------------------------------------------------------------

*GLT.hdr  HEADER FILE FOR GEOMETRIC LOOKUP TABLE (GLT.HDR) DATA
                 
Contents:  Format of each *GLT file.  This file contains the number of 
           lines, samples, channel, integer format, pixel size, scene 
           elevation, UTM zone number and rotation angle information, etc.
           
File type: ASCII

-------------------------------------------------------------------------------

*IGM  INPUT GEOMETRY FILE (IGM)

Contents:  Pixel location data for each radiance image cube. The IGM file data 
           contain three parameters:
           1) WGS-84 longitude (reported in decimal degrees)
           2) WGS-84 latitude (reported in decimal degrees)
           3) Estimated ground elevation at each pixel center 
              (reported in meters)
                
           No map correction or resampling is applied to the radiance image 
           cube; the IGM file only reports the surface location of the 
           unadjusted pixel centers.

File type: BINARY 64-bit double precision, floating point IEEE.

Units:     Band 1 - decimal degrees
           Band 2 - decimal degrees
           Band 3 - meters

Format:    Band interleaved by line 

----------------------------------------------------------------------------

*IGM.hdr  HEADER FILE FOR INPUT GEOMETRY FILE (IGM) DATA

Contents:  Format of each *ort_igm file.  This file contains the number of 
           lines, samples, channel, integer format, etc.

File type: ASCII

----------------------------------------------------------------------------

*RDN_ORT CALIBRATED AVIRIS-3 RADIANCE (IMAGE) DATA

Contents:  AVIRIS-3 calibrated radiance 

File type: BINARY 32-bit little-endian floating point IEEE.

Units:     microwatts per centimeter_squared per nanometer per steradian

Format:    Band interleaved by line 

--------------------------------------------------------------------------------

*RDN_ORT.hdr HEADER FILE FOR CALIBRATED AVIRIS-3 RADIANCE (IMAGE) DATA

Contents:  Format of each AVIRIS-3 calibrated radiance scene.  This file 
           contains the number of lines, samples, channel, etc. It also records 
           the spectral calibration (wavelength and full-width at half-maximum 
           value) for every channel in the radiance data.

File type: ASCII

----------------------------------------------------------------------------

*RFL_ORT     CALIBRATED AVIRIS-3 REFLECTANCE (IMAGE) DATA

Contents:  AVIRIS-3 surface reflectance
           
File type: BINARY 32-bit little-endian floating point IEEE.
           
Units:     Apparent surface reflectance (Thompson et al., 2018,
               Thompson et al., 2019, Thompson et al., 2020)
           
Format:    Band interleaved by line 

--------------------------------------------------------------------------------

*RFL_ORT.hdr   HEADER FILE FOR CALIBRATED AVIRIS-3 REFLECTANCE (IMAGE) DATA

Contents:  Format of each AVIRIS-3 calibrated reflectance scene.  
           This file contains the number of lines, samples, channel, etc. It 
           also records the spectral calibration (wavelength and full-width at 
           half-maximum values) for every channel in the reflectance data.            

File type: ASCII


----------------------------------------------------------------------------

*UNC_ORT     CALIBRATED AVIRIS-3 REFLECTANCE UNCERTAINTY (IMAGE) DATA

Contents:  AVIRIS-3 surface reflectance uncertainty
           
File type: BINARY 32-bit little-endian floating point IEEE.
           
Units:     Apparent surface reflectance (Thompson et al., 2018,
               Thompson et al., 2019, Thompson et al., 2020)
           
Format:    Band interleaved by line 

--------------------------------------------------------------------------------

*UNC_ORT.hdr   HEADER FILE FOR CALIBRATED AVIRIS-3 REFLECTANCE UNCERTAINTY (IMAGE) DATA

Contents:  Format of each AVIRIS-3 calibrated reflectance uncertainty scene.  
           This file contains the number of lines, samples, channel, etc. It 
           also records the spectral calibration (wavelength and full-width at 
           half-maximum values) for every channel in the uncertainty data.            

File type: ASCII

----------------------------------------------------------------------------

*.yaml     DATA PRODUCT METADATA

Contents:  Contains metadata for each data product including input files and PGE parameters.
           
File type: YAML

File type: ASCII


--------------------------------------------------------------------------------
REFERENCES
--------------------------------------------------------------------------------

D. R. Thompson, V. Natraj, R. O. Green, M. C. Helmlinger, B. C. Gao, M. L. Eastwood, Optimal estimation for imaging spectrometer atmospheric correction, Remote Sens. Env., 
216, 355-373, 2018. 

D. R. Thompson, K.N. Babu, A. J. Braverman, M. L. Eastwood, R. O. Green, J. M. Hobbs, J. B. Jewell, B. Kindel, S. Massie, M. Mishra, A. Mathur, V. Natraj, P. A. Townsend, F. C. Seidel, M. J. Turmon, Optimal estimation of spectral surface reflectance in challenging atmospheres, Remote Sens. Env., 232, 111258, 2019.

D. R. Thompson, A. Braverman, P. G. Brodrick, A. Candela, N. Carmon, R. N. Clark, D. Connelly, R. O. Green, R. F. Kokaly, L. Li, N. Mahowald, R. L. Miller, G. S. Okin, T. H. Painter, G. A. Swayze, M. Turmon, J. Susilouto, D. S. Wettergreen, Quantifying uncertainty for remote spectroscopy of surface composition, Remote Sens. Env., 247, 111898, 2020.

--------------------------------------------------------------------------------
ACKNOWLEDGEMENTS
--------------------------------------------------------------------------------

This research was performed at the Jet Propulsion Laboratory, California 
Institute of Technology, under contract with the National Aeronautics and 
Space Administration (NASA).  We are grateful for the help and assistance of 
colleagues including Bo-Cai Gao (NRL), Ian McCubbin (JPL), Dar Roberts (UCSB),
Mark Helmlinger (JPL), Scott Nolte (JPL), Ernie Diaz (JPL), Daniel Nunes (JPL),
and the rest of the AVIRIS-3 team. Copyright 2016 California Institute of 
Technology.  All Rights Reserved.  U.S. Government Support Acknowledged.

--------------------------------------------------------------------------------
MODIFICATIONS
--------------------------------------------------------------------------------
6 Feb  . 2016 (D. R. Thompson) - Minor updates, translated back to AVIRIS-3
21 Sept. 2014 (D. R. Thompson) - Translated from AVIRIS-3 to PRISM
10 Sept. 2014 (D. R. Thompson) - Initial document
