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MOLA Mission Experiment Gridded Data Record (MEGDR)

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MEGDR – Mission Experiment Gridded Data Record

 

Instrument: Mars Orbiter Laser Altimeter

PDS Data Set ID: MGS-M-MOLA-5-MEGDR-L3-V1.0

For more information about MOLA MEGDR products, see the Data Set Catalog File and the MOLA EGDR Product SIS.

 

The Mars Orbiter Laser Altimeter (MOLA) Mission Experiment Gridded Data Record (MEGDR) data product is a global map of planetary radius, aeroid, topography, and number of observations, derived from MOLA Precision Experiment Data Record (PEDR) products and aggregated into latitude-longitude bins.  The binned data include all MOLA nadir observations from the Mapping Phase through the Primary and Extended missions, from the end of aerobraking in February 1999 through June 2001.

 

Additionally, off-nadir observations of the north pole are included from 87N latitude and northward, taken during the spring of 1998, and of both poles taken during Mapping from 87N and 87S to the poles.

 

Data are adjusted using a first-order crossover solution for radial, along-track, and across-track position.  Parts of orbits are excluded where solutions for these orbits are deemed to be poor.  Also excluded are shots more than 1.2 degree off-nadir (except as noted above), channel 4 returns, and any returns not classified as ground returns, e.g. clouds or noise.  A total of nearly 600,000,000 observations are represented.

 

MOLA MEGDR non-polar products have the following file names:

MEGkaadooorv.IMG (with detached PDS label)

where:

k = image type

A = aeroid

C = counts

R = radius

T = topography

aa = 2-digit latitude of the pixel in upper left corner of the image

d = latitude direction

N = North

S = South

ooo = 3-digit longitude of the pixel in the upper left corner of the image

r = map resolution in pixels per degree

C = 4 pix/deg

E = 16 pix/deg

F = 32 pix/deg

G = 64 pix/deg

H = 128 pix/deg

v = version letter

 

MOLA MEGDR counts and radius polar products have the following file names:

MEGk_d_rrr.IMG (with detached PDS label)

where:

k = image type

C = counts

R = radius

d = latitude direction

N = North

S = South

rrr = map resolution in pixels per degree (128, 256, or 512 pix/deg)

 

MOLA MEGDR topography polar products have the following file names:

MEGT_d_rrr_v.IMG

where:

d_rrr = same as polar products above

v = version number

 

In ODE, MEGDR products have one of the following product IDs:

MEGKAADOOORV.IMG

MEGK_D_RRR.IMG

MEGT_D_RRR_V.IMG