MRO CRISM VNIR Hyperspectral Reduced Data Record (VRDR)

Instrument:Compact Reconnaissance Imaging Spectrometer for Mars

PDS3 Data Set ID:MRO-M-CRISM-5-RDR-VNIRHYPERSPECTRAL-V1.0DOI: 10.17189/tt67-sj14

PDS4 Bundle:urn:nasa:pds:mro_crism_vrdrDOI: 10.17189/qgxh-3r49

For more information about CRISM products, go to the CRISM Product Primer.

For more information about VRDRs, see the CRISM Archive Volume SIS.

A map-projected VNIR Hyperspectral Reduced Data Record (VRDR) consists of several or more strips of VNIR hyperspectral mapping data mosaicked into a map tile. Thus a VRDR map tile is constructed from a large number of VNIR-only TRDRs. The mosaic is uncontrolled (accepting existing pointing data with image mismatch at seams generally less than one ~90-m pixel). The same global pattern of 1964 such tiles as with MRDRs is used, forming a major data product for VNIR hyperspectral mapping. For each tile Lambert albedo, summary products, and the DDR data used to generate them are included as separate multiband images. So, for every latitude or longitude in a VRDR, there is both a Lambert spectral albedo and all the information providing traceability to the source TRDR in sensor space. The VRDRs also include text files having information on the wavelength of the layers of the Lambert albedo multiband image.

The VRDR data processing flow is the same as for version 4 MRDRs, except using only the steps that are needed for VNIR data. Specifically, four steps are omitted. There is no ATM correction or Radiative Transfer Correction step, and no spatial transformation of VNIR to IR detector space or combination of VNIR and IR data. All other steps remain applicable.

The VRDR data processing pipeline is described in more detail in Appendix P4 CRISM Data Product SIS..

The VRDRs are organized into 30 subdirectories named by the Mars Chart containing the VRDR, e.g. MC01, following the same organizational structure of MRDRs. Latitude and longitude limits of Mars Charts are given in Table 3-12 CRISM Archive Volume SIS..

 

CRISM VRDR products have the following file names:

TNNNN_TTTSS_XXDYYY_RRRR_V.(Ext) - The product ID scheme for the CRISM VRDRs

TNNNN_TTTBBB_XXDYYY_RRRR_V - The product ID scheme for the CRISM VRDR browse products

where:

TNNNN = tile number with tile 0001 at the south pole, increasing spiraling east northward

TTT = Product Type ("VRR" for VRDR)

SS = Product subtype, i.e., AL, SU, DE, or WV

AL – Lambert albedo

SU – Summary Products

DE – Derived Products

WV – List of wavelengths and wavelength ranges of radiance and I/F images

BBB = Browse Product Type, TRU, VNA, FEM, or FM2

XX = Planetocentric latitude of tile center

D = N or S for north or south latitude

YYY = East longitude of tile center (rounded)

RRRR = Map resolution in pixels per degree, e.g. 0654, 0256 or 0327

V = Product version number such as 0, 1,..., 9, a,..., z

Ext = IMG, TAB, XML, or LBL

In ODE, VRDR products have the following Product IDs:

TNNNN_VRRSS_XXDYYY_0654_1