MESSENGER UVVS Spectral Cube of Mercury (MEAP-2)

MEAP2 – UVVS Spectral Cube Derived Analysis Product

Instrument: Mercury Atmospheric and Surface Composition Spectrometer

PDS Bundle: urn:nasa:pds:izenberg_pdart14_meapDOI: 10.17189/1518648

PDS Collection: urn:nasa:pds:izenberg_pdart14_meap:data_imagecube

For more information about MEAP products, see the Messenger Advanced Product Specification.

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) Ultraviolet and Visible Spectrometer (UVVS) Spectral Cube Derived Analysis Product (MEAP2) consists of map-projected photometrically normalized I/F DDRs mosaicked into a hyperspectral map tile. MEAP2 comprises 3 separate sub-cubes: 1) the Reflectance Cube; 2) the Footprint ID Cube; and 3) the Backplanes Cube. Reflectance and Footprint ID Cube data are 43 non-overlapping, 64 pixel/degree tiles similar to the Mercury Dual Imaging System’s (MDIS) 8-color imaging RDR of Mercury.

Individual footprint pixels where UVVS data exists and multiple observations overlap are determined by ‘best’ UVVS spectra, determined by a quality factor using favorable geometry (max (cos (e) * cos(i)) ) and spatial coverage (smaller footprints are given higher quality factor).

Data are corrected photometrically to incidence angle=45 degrees, emission angle=45 degrees, phase angle=90 degrees, at a resolution of 64 pixels per degree (~665 m/pixel at the equator). Hyperspectral data is composed of up to 46 spectral bands corresponding to 660 binned steps of the UVVS spectrum from 210 to 300 nm, with ~2 nm wavelength bins.

A UVVS Footprint ID Cube DAP is the same dimensions as the UVVS Spectral Cube. It consists of a pixel by pixel identification of the observation from which the spectral data in the corresponding pixel of the Spectral Cube DAP.

The Backplane Cube DAP contains one band for each backplane (9 in total), one row for each footprint (4529 total), one column for each cube wavelength (46). There are 8 backplanes for the hyperspectral data:

  1. incidence angle of the original spectrum,

  2. emission angle of the original spectrum,

  3. phase angle of the original spectrum,

  4. observation area of the UVVS center step footprint of the UVVS spectrum

  5. drift of the instantaneous footprint in km across the surface from first to last step

  6. smear of the footprint in fractions of the instantaneous field of view

  7. qualitative measure of surface variability

  8. DDR date and (i) DDR time of UVVS observation.

The wavelength file is an ASCII file with the layer numbers and wavelengths of the spectral layers of the UVVS Cube. The file is named UVVS_WAVELENGTHS.TAB.

MEAP2 products have the following file names:



64PPD = map scale, 64 pixels per degree

Hxx = Mercury chart designation

dd = quadrant within Mercury chart (NW, NE, SW, or SE) or a polar chart (NP, SP)

fid = footprint ID cube. Files without this suffix are the spectral reflectance cubes themselves.


The backplanes cube is a single file of 4529 (footprints) * 46 (wl cube bands) * 9 (backplanes).

MEAP2 PDS4 Logical Identifiers:




Mercury Charts, as named at the end of mission delivery:



Latitude (degrees)

Longitude (degrees east)

H-1 Borealis


65 to 90

0 to 360

H-2 Victoria


22.5 to 65

270 to 360

H-3 Shakespeare


22.5 to 65

180 to 270

H-4 Raditladi


22.5 to 65

90 to 180

H-5 Hokusai


22.5 to 65

0 to 90

H-6 Kuiper


-22.5 to 22.5

288 to 360

H-7 Beethoven


-22.5 to 22.5

216 to 288

H-8 Tolstoj


-22.5 to 22.5

144 to 216

H-9 Eminescu


-22.5 to 22.5

72 to 144

H-10 Derain


-22.5 to 22.5

0 to 72

H-11 Discovery


-65 to -22.5

270 to 360

H-12 Michelangelo


-65 to -22.5

180 to 270

H-13 Neruda


-65 to -22.5

90 to 180

H-14 Debussey


-65 to -22.5

0 to 90

H-15 Bach


-90 to -65

0 to 360