LRO LOLA Gridded Data Record Slope Map (GDRDSM)
GDRDSM – Gridded Data Record Slope Map
Instrument: Lunar Orbiter Laser Altimeter
PDS Data Set ID: LRO-L-LOLA-4-GDR-V1.0
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.
The Lunar Orbiter Laser Altimeter (LOLA) Gridded Data Record Slope Map (GDRDSM) data product is a map of the surface slope of the Moon, based on altimetry data acquired by the LOLA instrument. The bi-directional slope was calculated from a plane fit to three successive laser shots requiring n=5 to 15 profile returns. Depending on orbital velocity, probability of detection and spacecraft altitude, the slope baseline may vary from 30 to 120 meters.
The slope is scaled and offset.
Slope = DN * SCALING_FACTOR + OFFSET. (DN = Digital Number)
A pixel in the GDRDSM 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.
Equirectangular map-projected slope maps
|
Product |
Pixel size (latitude) |
Number/size of tiles |
Bits per pixel |
|
LDSM_16 |
1.8952 km |
Global, 0-360 |
16 |
Polar map-projected slope maps, N/S
|
Product |
dimensions |
Pixel size |
Latitude range |
Bits per pixel |
|
LDSM_75S_240M |
3812 x 3812 |
240 x 240 m |
+/- 75° to pole |
16 |
|
LDSM_75S_120M |
7624 x 7624 |
120 x 120 m |
+/- 75° to pole |
16 |
|
LDSM_85S_40M |
7584 x 7584 |
40 x 40 m |
+/- 85° to pole |
16 |
LOLA GDRDSM products have the following file names:
productsuffix
where:
product = product name above
suffix = file type/extension
.IMG = image file
.LBL = detached PDS label
.JP2 = JPEG2000 file
_JP2.LBL = detached PDS label
In ODE, GDRDSM products have the following product IDs:
PRODUCT