=============================================================================== AVIRIS-NG Data Product Distribution Document =============================================================================== Sarah R. Lundeen, Sarah.R.Lundeen@jpl.nasa.gov Robert O. Green, Robert.O.Green@jpl.nasa.gov Michael Eastwood, meastwood@jpl.nasa.gov David R. Thompson, David.R.Thompson@jpl.nasa.gov This document describes the AVIRIS Next Generation (AVIRIS-NG) L1 and L2 data products. AVIRIS-NG is an imaging spectrometer that measures reflected radiance at 5nm intervals in the Visible/Short-Wave Infrared (VSWIR) spectral range from 380-2500nm. Additional information may be found on http://avirisng.jpl.nasa.gov ------------------------------------------------------------------------------- OVERVIEW ------------------------------------------------------------------------------- Each flightline uses a specific base filename prefix: angYYYYMMDDtHHNNSS 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 The AVIRIS-NG data products for a particular airborne flight run are organized in the following directory structure, labeled with a processing version marker VVV: /YYYYMMDDtHHNNSS_VVV | angYYYYMMDDtHHNNSS_h2o_VVV_img | angYYYYMMDDtHHNNSS_h2o_VVV_img.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_img | angYYYYMMDDtHHNNSS_rdn_VVV_img.hdr | angYYYYMMDDtHHNNSS_corr_VVV_img | angYYYYMMDDtHHNNSS_corr_VVV_img.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_glt | angYYYYMMDDtHHNNSS_rdn_VVV_glt.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_igm | angYYYYMMDDtHHNNSS_rdn_VVV_igm.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_loc | angYYYYMMDDtHHNNSS_rdn_VVV_loc.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_obs | angYYYYMMDDtHHNNSS_rdn_VVV_obs.hdr | angYYYYMMDDtHHNNSS_rdn_VVV_obs_ort | angYYYYMMDDtHHNNSS_rdn_VVV_obs_ort.hdr The file product codes signify: *rdn_obs_ort parameters relating to the geometry of observation and illumination rendered using the *glt lookup table *rdn_VVV_obs_ort.hdr obs_ort image header file *rdn_obs parameters relating to the geometry of observation and illumination in the raw spatial format *rdn_VVV_obs.hdr obs image header file *rdn_VVV_glt geometric look-up table *rdn_VVV_glt.hdr GLT image header file *rdn_VVV_igm input geometry file *rdn_VVV_igm.hdr IGM image header file *rdn_VVV_loc pixel location data file *rdn_VVV_loc.hdr LOC image header file *rdn_VVV_img orthocorrected, scaled radiance image file *rdn_VVV_img.hdr RDN image header file *corr_VVV_img orthocorrected, scaled reflectance image file *corr_VVV_img.hdr CORR image header file *h2o_VVV_img orthocorrected water absorption data *h2o_VVV.hdr H2O header file ------------------------------------------------------------------------------ FILE DESCRIPTIONS ------------------------------------------------------------------------------ *rdn_VVV_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 32-bit signed long integer. Format: Band interleaved by pixel ------------------------------------------------------------------------------ *rdn_VVV_glt.hdr HEADER FILE FOR GEOMETRIC LOOKUP TABLE (GLT.HDR) DATA Contents: Format of each *rdn_VVV_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 ------------------------------------------------------------------------------- *rdn_VVV_igm INPUT GEOMETRY FILE (IGM) Contents: UTM ground locations (x,y,elevation) in meters for each pixel in the corresponding unorothcorrected radiance image. The IGM file data contain three parameters: 1) Easting (meters) 2) Northing (meters) 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 32-bit signed long integer. Units: Band 1 - meters Band 2 - meters Band 3 - meters Format: Band interleaved by pixel ---------------------------------------------------------------------------- *rdn_VVV_igm.hdr HEADER FILE FOR INPUT GEOMETRY FILE (IGM) DATA Contents: Format of each *rdn_VVV_igm file. This file contains the number of lines, samples, channel, integer format, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_img CALIBRATED PRISM RADIANCE (IMAGE) DATA Contents: PRISM calibrated radiance File type: BINARY 32-bit big-endian floating point Intel. Units: microwatts per centimeter_squared per nanometer per steradian Format: Band interleaved by line -------------------------------------------------------------------------------- *rdn_VVV_img.hdr HEADER FILE FOR CALIBRATED PRISM RADIANCE (IMAGE) DATA Contents: Format of each PRISM 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 ---------------------------------------------------------------------------- *rdn_VVV_loc PIXEL LOCATION DATA (LOC) Contents: Pixel locations (WGS-84 lat/lon) for each science pixel in the corresponding unorthocorrected radiance image. The LOC file data contain three parameters: 1) WGS-84 longitude (decimal degrees) 2) WGS-84 latitude (decimal degrees) 3) Estimated ground elevation at each pixel center (reported in meters) File type: BINARY 64-bit double-precision, floating point. Units: Band 1: decimal degrees Band 2: decimal degrees Band 3: meters Format: Band interleaved by line -------------------------------------------------------------------------------- *rdn_VVV_loc.hdr HEADER FILE FOR PIXEL LOCATION DATA (LOC) Contents: Format of each PRISM *loc file. This file contains the number of lines, samples, channel, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_obs OBSERVATION PARAMTER FILE (OBS) Contents: Observation parameter files in the raw spatial format; matches the corresponding unorthocorrected radiance image. The OBS file data contain eleven parameters: 1) path length (sensor-to-ground in meters) 2) to-sensor-azimuth (0 to 360 degrees clockwise from N) 3) to-sensor-zenith (0 to 90 degrees from zenith) 4) to-sun-azimuth (0 to 360 degrees clockwise from N) 5) to-sun-zenith (0 to 90 degrees from zenith) 6) solar phase (degrees between to-sensor and to-sun vectors in principal plane) 7) slope (local surface slope as derived from DEM in degrees) 8) aspect (local surface aspect 0 to 360 degrees clockwise from N) 9) cosine i (apparent local illumination factor based on DEM slope and aspect and to sun vector, -1 to 1) 10) UTC time (decimal hours for mid-line pixels) 11) Earth-sun distance (AU) File type: BINARY 64-bit double-precision, floating point. Format: Band interleaved by pixel -------------------------------------------------------------------------------- *rdn_VVV_obs.hdr OBSERVATION PARAMETER FILE (OBS) Contents: Format of each PRISM *obs file. This file contains the number of lines, samples, channel, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_obs_ort ORTHOCORRECTED OBSERVATION PARAMTER FILE (OBS ORT) Contents: Observation parameter file that has been rendered using the GLT lookup table and matches the orthocorrected imagery. The OBS ORT file data contain eleven parameters: 1) path length (sensor-to-ground in meters) 2) to-sensor-azimuth (0 to 360 degrees clockwise from N) 3) to-sensor-zenith (0 to 90 degrees from zenith) 4) to-sun-azimuth (0 to 360 degrees clockwise from N) 5) to-sun-zenith (0 to 90 degrees from zenith) 6) solar phase (degrees between to-sensor and to-sun vectors in principal plane) 7) slope (local surface slope as derived from DEM in degrees) 8) aspect (local surface aspect 0 to 360 degrees clockwise from N) 9) cosine i (apparent local illumination factor based on DEM slope and aspect and to sun vector, -1 to 1) 10) UTC time (decimal hours for mid-line pixels) 11) Earth-sun distance (AU) File type: BINARY 64-bit double-precision, floating point. Format: Band interleaved by pixel -------------------------------------------------------------------------------- *rdn_VVV_obs_ort.hdr ORTHOCORRECTED OBSERVATION PARAMETER FILE (OBS ORT) Contents: Format of each PRISM *obs_ort file. This file contains the number of lines, samples, channel, etc. File type: ASCII ---------------------------------------------------------------------------- *corr_VVV_img CALIBRATED AVIRIS-NG REFLECTANCE (IMAGE) DATA Contents: AVIRIS-NG calibrated reflectance File type: BINARY 32-bit little-endian floating point IEEE. Units: Apparent surface reflectance (Gao et al., 1993) Format: Band interleaved by line -------------------------------------------------------------------------------- *corr_VVV_img.hdr HEADER FILE FOR CALIBRATED AVIRIS REFLECTANCE (IMAGE) DATA Contents: Format of each AVIRIS 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 values) for every channel in the radiance data. The "Smoothing factors" field contains a list of multiplicative coefficients applied to smooth the resulting reflectance spectrum. These coefficients were derived from Calibration measurements using spectrally-invariant surface targets. To remove this correction simply divide the apparent reflectance by these values. File type: ASCII ---------------------------------------------------------------------------- *h2o_VVV WATER ABSORPTION PATH (IMAGE) DATA Contents: Retrieved column water vapor and optical absorption paths for liquid H2O and ice File type: BINARY 32-bit little-endian floating point IEEE. Units: Band 1: Retrieved column H2O vapor in cm Band 2: Total liquid H2O absorption path in cm Band 3: Total ice absorption path in cm Format: Band interleaved by line -------------------------------------------------------------------------------- *h2o_VVV.hdr HEADER FILE FOR WATER ABSORPTION PATH (IMAGE) DATA Contents: Format of each AVIRIS-NG H2O cene. This file contains the number of lines, samples, channel, etc. File type: ASCII -------------------------------------------------------------------------------- REFERENCES -------------------------------------------------------------------------------- Gao, B.C., K. H. Heidebrecht, and A. F. H. Goetz, Derivation of scaled surface reflectances from AVIRIS data, Remote Sens. Env., 44, 165-178, 1993 -------------------------------------------------------------------------------- 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), Yasha Mouradi (JPL), and the rest of the AVIRIS-NG team. Copyright 2014 California Institute of Technology. All Rights Reserved. U.S. Government Support Acknowledged. -------------------------------------------------------------------------------- MODIFICATIONS -------------------------------------------------------------------------------- 10 Sept. 2014 (D. R. Thompson) - Initial document 25 July 2016 (S. R. Lundeen) - Revision to orthorectified data products 13 Oct. 2016 (S. R. Lundeen) - Added obs_ort file description