Astrogeology Science Center

LRO LOLA and Kaguya Terrain Camera DEM Merge 60N60S 512ppd (59m)

The LOLA and Kaguya Teams have created an improved lunar digital elevation model (DEM) covering latitudes within ±60°, at a horizontal resolution of 512 pixels per degree (∼59 m at the equator) and a typical vertical accuracy ∼3 to 4 m. This DEM is constructed from ∼4.5×109 geodetically-accurate topographic heights from the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter, to which we co-registered 43,200 stereo-derived DEMs (each 1°×1°) from the SELENE Terrain Camera (TC) (∼1010 pixels total). After co-registration, approximately 90% of the TC DEMs show root-mean-square vertical residuals with the LOLA data of <5 m compared to ∼50% prior to co-registration. We use the co-registered TC data to estimate and correct orbital and pointing geolocation errors from the LOLA altimetric profiles (typically amounting to <10 m horizontally and <1 m vertically). By combining both co-registered datasets, we obtain a near-global DEM with high geodetic accuracy, and without the need for surface interpolation. We evaluate the resulting LOLA + TC merged DEM (designated as “SLDEM2015”) with particular attention to quantifying seams and crossover errors. Map values are referred to a radius of 1737400 m.

SELENE is a Japanese mission developed and operated by JAXA. Please credit NASA's LOLA Team and JAXA's SELENE/Kaguya Team.

Reference: Barker, M.K., E. Mazarico, G.A. Neumann, M.T. Zuberc, J. Haruyama, D.E. Smith, (2016), A new lunar digital elevation model from the Lunar Orbiter Laser Altimeter and SELENE Terrain Camera, Icarus, Volume 273, Pages 346–355 doi:10.1016/j.icarus.2015.07.039.

Publisher

Goddard Space Flight Center

Publication Date

4 February 2015

Author

LOLA Team and Kaguya Team

Originator

Group

PDS

Added to Astropedia

8 September 2015

Modified

4 March 2018

General

Purpose

This product was produced to generate a high-resolution global topographic model and geodetic framework that enables precise targeting, safe landing, and surface mobility to carry out exploratory activities. It can characterize the polar illumination environment, and images permanently shadowed polar regions of the Moon to identify possible locations of surface ice crystals in shadowed polar craters.

Geospatial Data Presentation Form

Topographic Map, Remote-sensing Data, Digital Elevation Model

SLDEM

Feburary 4, 2015

Online Linkage

https://planetarymaps.usgs.gov/mosaic/LolaKaguya_Topo/Lunar_LRO_LrocKaguya_DEMmerge_60N60S_512ppd.tif

Native Data Set Environment

ISIS v3, GDAL

Supplemental Information

http://dx.doi.org/10.1016/j.icarus.2015.07.039, http://pds-geosciences.wustl.edu/lro/lro-l-lola-3-rdr-v1/lrolol_1xxx/data/sldem2015/

Keywords

System

Earth

Target

Moon

Theme

Topography, Photogrammetry, Remote Sensing

Mission

Lunar Reconnaissance Orbiter, Kaguya

Mission Specific

Terrain Camera Stereo

Instrument

LOLA, TC

Search Terms

SLDEM, DEM, DTM, LOLA, Kakuya, Selene, JAXA

Contact and Distribution

Access Constraints

public domain

Use Constraints

Please cite authors

Data Status and Quality

Currentness Reference

Publication date

Progress

Complete

Update Frequency

As needed

Logical Consistency Report

To reduce the presence of the largest seams, the team replaced the most poorly fit ∼1% of tiles with the original LOLA-only DEMs with interpolation to fill gaps.

Completeness Report

Only available from -60 to 60 degrees in latitude

Process Date

4 February 2015

Process Description

Errors in the TC tiles result from imperfect knowledge of the Kaguya orbit, as well as errors in camera pointing, focal length, flat-field, distortion, and jitter. Offsets in the LOLA profiles are due largely to orbit uncertainties and errors in the laser boresight model. To isolate these error sources, the authors followed a two-step approach when co-registering the TC tiles to the LOLA data. In step (1), they derived a 5-parameter coordinate transformation between every TC tile and the full resolution LOLA data in that tile (unbinned point cloud with ∼100, 000 points). Given the large number of individual profiles (typically ∼70 per tile), they expected the LRO/LOLA orbital and pointing errors to average out to very nearly zero in any given tile given they are uncorrelated over the ∼4 years of acquisition. Thus, the tile-averaged transformation parameters compensate predominantly for the Kaguya/TC orbital, pointing, and camera model errors. In step (2), they fit a 3-dimensional (3D) offset to each LOLA profile segment in the transformed TC tile. These offsets reflect primarily the LOLA geolocation errors described above with a secondary contribution from Kaguya/TC errors not completely removed by the transformation in step (1) due to the low number of degrees of freedom.

Horizontal Positional Accuracy Value

10

Horizontal Positional Accuracy Report

Accurate to Control Net

Vertical Positional Accuracy Value

4

Vertical Positional Accuracy Report

Accurate to Control Net

Entity and Attribute Overview

elevation in meters

Entity and Attribute Detailed Description

Conversion to local height (meters) is accomplished via the following equation:
Height = (Pixel Value * Scaling Factor)
Conversion to local Radius (meters) is computed as follows:
Radius = (Pixel Value * Scaling factor) + 1737400
where Scaling Factor = 0.5 (as listed in the label as Multiplier)

e.g. conversion using GDAL tools: >gdal_translate -unscale -ot float23 -co bigtiff=if_safer in.cub out_32bit.cub

Elevations were originally computed by subtracting the lunar reference radius of 1737400.0 m from the surface radius measurements. Thus elevation values are the distance above or below the reference sphere.

Lineage

Source Originator

Planetary Data System

Source Publication Date

4 February 2015

Source Title

SLDEM2015: a merged LOLA Kaguya Lunar DEM

Source Online Linkage

http://pds-geosciences.wustl.edu/lro/lro-l-lola-3-rdr-v1/lrolol_1xxx/data/sldem2015/

Type of Source Media

Online

Attribute Accuracy Report

Accurate to Control Net

Geospatial Information

Location Description

Moon

Minimum Latitude

-60

Maximum Latitude

60

Minimum Longitude

-180

Maximum Longitude

180

Direct Spatial Reference Method

Raster

Object Type

Pixel

Lines (pixels)

61440

Samples (pixels)

184320

Bit Type

16

Quad Name

Radius A

1737400

Radius C

1737400

Control Net

LOLA

Bands

1

Pixel Resolution (meters/pixel)

59.2252938

Scale (pixels/degree)

512

Horizontal Coordinate System Units

Meters

Map Projection Name

Equirectangular

Latitude Type

Planetocentric

Longitude Direction

Positive East

Longitude Domain

-180 to 180