LRO LOLA Gridded Data Record (GDR)

GDR – Gridded Data Records

Instrument: Lunar Orbiter Laser Altimeter

For more information about LOLA RDR and derived products, see the RDR Product SIS.

For more information about all LOLA products, see the LOLA Archive Volume SIS.

Information about JPEG 2000

The Lunar Orbiter Laser Altimeter (LOLA) Gridded Data Records (GDR) data products are resampled at uniform intervals, in both cylindrical and polar projections. They contain the binned, interpolated altimetric measurements, as well as albedo, roughness, and surface slope both. Each map type can be found below.

A pixel in the GDR product represents the mean value at the center of a region bounded by lines of constant longitude and latitude at integral numbers of degrees or fractions thereof, scaled and interpolated where necessary. The size of the products at higher resolutions requires that they be aggregated in subsets of global coverage. Global standard products use the Equirectangular map projection, also known as Simple Cylindrical, while the higher-resolution products afforded by dense polar coverage use the Polar Stereographic projection. See images of both projections below the table.

Type	Description	Data Set ID
GDRDAM	Gridded Data Record - Albedo (brightness) Maps	LRO-L-LOLA-4-GDR-V1.0
GDRDAC	Data counts to generate albedo maps	LRO-L-LOLA-4-GDR-V1.0
GDRDEM	Gridded Data Record - Terrain Shape Map NOTE: As per the label, height values are scaled and offset. Please review label note on HEIGHT conversion: /* NOTE: / / Conversion from Digital Number to HEIGHT, i.e. elevation in meters, is: / / HEIGHT = (DN * SCALING_FACTOR). / / The conversion from Digital Number to PLANETARY_RADIUS in meters is: / / PLANETARY_RADIUS = (DN * SCALING_FACTOR) + OFFSET / / where OFFSET is the radius of a reference sphere. / / The planetopotential TOPOGRAPHY is PLANETARY_RADIUS - GEOID_RADIUS, / / where GEOID_RADIUS is derived from a gravitational equipotential model. / / By convention, the average GEOID_RADIUS at the equator is OFFSET. */	LRO-L-LOLA-4-GDR-V1.0
GDRDEC	Gridded Data Record - Shape Map Counts	LRO-L-LOLA-4-GDR-V1.0
GDRDRM	Gridded Data Record - Surface Roughness Map More Information: Rosenburg, M.A., Aharonson, O., Head, J. W., Kreslavsky, M.A., Mazarico, E., Neumann, G.A., Smith, D.E, Torrence, M.H., Zuber, M.T. (2011), Global Surface Slopes and Roughness of the Moon from the Lunar Orbiter Laser Altimeter, Journal of Geophysical Research, 116, E02001, doi: 10.1029/2010JE003716. The LOLA team has included a set of “extra” products that include maps of the coefficients that indicate a measure of surface roughness at http://imbrium.mit.edu/EXTRAS/FRACTAL/. These products are available through ODE as RMHE and RMMAS products. See the README_FRACTAL.TXT for a description of these extra products. NOTE: As per the label, surface roughness value is scaled. Please see the label for more details. Roughness = DN * SCALING_FACTOR	LRO-L-LOLA-4-GDR-V1.0
GDRDRC	Data counts to generate roughness maps	LRO-L-LOLA-4-GDR-V1.0
GDRDSM	Gridded Data Record - Slope Map NOTE: As per the label, the slope map value is scaled and offset. Please see the label for more details. Slope = DN * SCALING_FACTOR + OFFSET	LRO-L-LOLA-4-GDR-V1.0
GDRDGM	Gridded Data Record - Geoid NOTE: As per the label, the geoid value is scaled and offset. Please see the label for more details. Geoid = DN * SCALING_FACTOR + OFFSET	LRO-L-LOLA-4-GDR-V1.0
GDRPSR	Gridded Data Record - Permanently Shadowed Map NOTE: As per the label, the permanently shadowed region value is scaled and offset. Please see the label for more details. Value = DN * SCALING_FACTOR + OFFSET	LRO-L-LOLA-4-GDR-V1.0
GDRSKY	Gridded Data Record - Sky Visibility NOTE: As per the label, the sky visibility value is scaled and offset. Please see the label for more details. Value = DN * SCALING_FACTOR + OFFSET	LRO-L-LOLA-4-GDR-V1.0
GDRVIS	Gridded Data Record of the average visibility of the Sun NOTE: As per the label, the the average_visibility value is scaled and offset. Please see the label for more details. Value = DN * SCALING_FACTOR + OFFSET	LRO-L-LOLA-4-GDR-V1.0

Equirectangular map projection. Lines show notional tiling subdivisions (in pixels/degree) of 256 (bold), 512 (fine), and 1024 (dashed).

Polar stereographic map projection from 45°N to pole. Circles show outlines of maps at various resolutions (innermost circles enclose 5 and 10 meters per pixel maps).