MESSENGER VIRS Spectral Cube of Mercury (MEAP-1)

MEAP1 – VIRS 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) Visible and Infrared Spectrograph (VIRS) Spectral Cube Derived Analysis Product (MEAP1) consists of VIRS spectral data map-projected, photometrically normalized, and mosaicked into hyperspectral map tiles. There are 54 non-overlapping, 64 pixel/degree tiles similar to the Mercury Dual Imaging System (MDIS) 8-color image of Mercury (RDRMDR).

Individual footprint pixels where VIRS data exists are determined by ‘best’ VIRS spectra, determined by a quality factor using favorable geometry [max(cos(e)*cos(i)), e = emission angle, i = incidence angle] 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 meters per pixel at the equator). Hyperspectral data is composed of up to 105 spectral bands corresponding to 105 binned wavelengths of the VIRS spectrum from 300 to 1450 nm, with ~9.3 nm wavelength bins between 300 and 900 nm and ~14 nm wavelength bands between 900 and 1450 nm.

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 VIRS spectrum

  5. Temperature of the NIR detector

  6. VIRS Calibrated Data Record (VIRSCDR) date (YYDOY)

  7. VIRSCDR time (HHMMSS)

  8. VIRSCDR spectrum number

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

MEAP1 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)

MEAP1 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