Mars MGS MOLA Elevation Model 463m (MEGDR)
This digital elevation model (DEM) is based on data from the Mars Orbiter Laser Altimeter (MOLA; Smith and others, 2001), an instrument on NASA’s Mars Global Surveyor (MGS) spacecraft (Albee and others, 2001). The DEM represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann and others, 2001, 2003) and converted to planetary radii. These have been converted to elevations above the areoid as determined from a Martian gravity field solution GMM-2B (Lemoine and others, 2001), truncated to degree and order 50, and oriented according to current standards. The average accuracy of each point is originally ~100 meters in horizontal position and ~1 meter in radius (Neumann and others, 2001). However, the total elevation uncertainty is at least ±3 m due to the global error in the areoid (±1.8 meters according to Lemoine and others [2001]) and regional uncertainties in its shape (G.A. Neumann, written commun., 2002).
References: * Albee, A.L., Arvidson, R.E., Palluconi, Frank, Thorpe, Thomas, 2001, Overview of the Mars Global Surveyor mission: Journal of Geophysical Research, v.106, no. E10, p. 23,291–23,316.
* de Vaucouleurs, Gerard, Davies, M.E., and Sturms, F.M., Jr., 1973, Mariner 9 areographic coordinate system, in Journal of Geophysical Research, v. 78, p. 4395–4404.
* Duxbury, T.C., Kirk, R.L., Archinal, B.A., and Neumann, G.A., 2002, MarsGeodesy/Cartography Working Group recommendations on Mars cartographicconstants and coordinate systems, in Joint International Symposiumon Geospatial Theory, Processing and Applications, Ottawa, Canada, 2002 Commission IV, Working Group 9—Extraterrestrial Mapping, Proceedings: Ottawa, Canada, International Society for Photogrammetry and Remote Sensing [http://www.isprs.org/commission4/proceedings/paper.html].
* Lemoine, F.G., Smith, D.E., Rowlands, D.D., Zuber, M.T., Neumann, G.A.,Chinn, D.S., Pavlis, D.E., 2001, An improved solution of the gravity field ofMars (GMM-2B) from Mars Global Surveyor: Journal of GeophysicalResearch, v. 106, no. E10, p. 23,359–23,376. * Neumann, G.A., Rowlands, D.D., Lemoine, F.G., Smith, D.E., and Zuber, M.T.,2001, Crossover analysis of Mars Orbiter Laser Altimeter data: Journal ofGeophysical Research, v. 106, no. E10, p. 23,753–23,768.
* Neumann, G. A., D. E. Smith, and M. T. Zuber, Two Mars years of clouds detected by the Mars Orbiter Laser Altimeter,J. Geophys. Res., 108(E4), 5023, doi:10.1029/2002JE001849, 2003.
* Seidelmann, P.K. (chair), Abalakin, V.K., Bursa, Milan, Davies, M.E., De Bergh,Catherine, Lieske, J.H., Oberst, Juergen, Simon, J.L., Standish, E.M.,Stooke, P.J., and Thomas, P.C., 2002, Report of the IAU/IAG WorkingGroup on Cartographic Coordinates and Rotational Elements of the Planetsand Satellites—2000: Celestial Mechanics and Dynamical Astronomy, v.82, p. 83–110.
* Smith, D.E., Sjogren, W.L., Tyler, G.L., Balmino, G., Lemoine, F.G., and Konopliv,A.S., 1999, The gravity field of Mars—Results from Mars Global Surveyor:Science, v. 286, p. 94–96.
* Smith, D.E., Zuber, M.T., Frey, H.V., Garvin, J.B., Head, J.W., Muhleman, D.O.,Pettengill, G.H., Phillips, R.J., Solomon, S.C., Zwally, H.J., Banerdt, W.B., Duxbury, T.C., Golombek, M.P., Lemoine, F.G., Neumann, G.A., Rowlands,D.D., Aharonson, Oded, Ford, P.G., Ivanov, A.B., Johnson, C.L., McGovern,P.J., Abshire, J.B., Afzal, R.S., and Sun, Xiaoli, 2001, Mars Orbiter LaserAltimeter—Experiment summary after the first year of global mapping ofMars: Journal of Geophysical Research, v. 106, no. E10, p. 23,689–23,722.
* Wessel, Paul, and Smith, W.H.F., 1998, New, improved version of Generic MappingTools released: Eos, Transactions of the American Geophysical Union,v. 79, no. 47, p. 579.
- Publisher
- Goddard Space Flight Center
- Author
- MOLA Team
- Originator
- USGS Astrogeology Science Center
- Group
- PDS
- Added to Astropedia
- 13 January 2014
- Modified
- 30 June 2017
General
- Purpose
The data from MOLA have been used to create the most accurate topographic map of Mars to date.
- Geospatial Data Presentation Form
- Digital Elevation Model, Topographic Map
- MOLA Mission Experiment Gridded Data Record
- MEGDR
- Edition
- 2003-03-21
- Online Linkage
- https://planetarymaps.usgs.gov/mosaic/Mars_MGS_MOLA_DEM_mosaic_global_463m.tif
- Native Data Set Environment
- ISIS v3
- Supplemental Information
- http://geo.pds.nasa.gov/missions/mgs/megdr.html
Keywords
Contact and Distribution
- Access Constraints
- Public domain
- Use Constraints
- Please cite authors
Data Status and Quality
- Logical Consistency Report
- The average accuracy of each point is originally ~100 meters in horizontal position and ~1 meter in radius (Neumann and others, 2001). However, the total elevation uncertainty is at least ±3 m due to the global error in the areoid (±1.8 meters according to Lemoine and others [2001]) and regional uncertainties in its shape (G.A. Neumann, written commun., 2002). The MOLA data were initially referenced to an internally consistent inertial coordinate system, derived from tracking of the MGS spacecraft. These values include the orientation of the north pole of Mars (including the effects of precession), the rotation rate of Mars, and a value for W0 of 176.630°, where W0 is the angle along the equator to the east, between the 0° meridian and the equator’s intersection with the celestial equator at the standard epoch J2000.0 (Seidelmann and others, 2002). This value of W0 was chosen (Duxbury and others, 2002) in order to place the 0° meridian through the center of the small (~500 m) crater Airy-0, within the crater Airy (Seidelmann and others, 2002; de Vaucouleurs and others, 1973). Longitude increases to the east and latitude is planetocentric as allowed by IAU/IAG standards (Seidelmann and others, 2002) and in accordance with current NASA and USGS standards (Duxbury and others, 2002).
- Completeness Report
Data are very sparse near the two poles (above 87° north and below 87° south latitude) because these areas were sampled by only a few off-nadir altimetry tracks. Gaps between tracks of 1–2 km are common, and some gaps of up to 12 km occur near the equator. DEM points located in these gaps in MOLA data were filled by interpolation.
- Process Description
The DEM represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann and others, 2001, 2003) and converted to planetary radii. These have been converted to elevations above the areoid as determined from a Martian gravity field solution GMM-2B (Lemoine and others, 2001), truncated to degree and order 50, and oriented according to current standards. The MOLA measurements were converted into a digital elevation model (DEM; G.A. Neumann, written commun., 2002; Neumann and others, 2001; Smith and others 2001) using Generic Mapping Tools software (Wessel and Smith, 1998), with a resolution of 128 pixels per degree. In projection, the pixels are 463 meters in size at the equator.
- Horizontal Positional Accuracy Value
- 100
- Horizontal Positional Accuracy Report
- Accurate to Control Net
- Vertical Positional Accuracy Value
- 1
- Vertical Positional Accuracy Report
- Accurate to Control Net
- Entity and Attribute Overview
- Elevation in meters.
- Entity and Attribute Detailed Description
- Elevations above the areoid as determined from a Martian gravity field solution GMM-2B (Lemoine and others, 2001).
- Entity and Attribute Linkage
- http://onlinelibrary.wiley.com/doi/10.1029/2000JE001426/abstract
Lineage
- Source Originator
- Goddard Space Flight Center
- Source Title
- MOLA Mission Experiment Gridded Data Records (MEGDRs)
- Source Online Linkage
- http://geo.pds.nasa.gov/missions/mgs/megdr.html
- Type of Source Media
- Online
- Attribute Accuracy Report
- Best Effort
Geospatial Information
- Minimum Latitude
- -90
- Maximum Latitude
- 90
- Minimum Longitude
- -180
- Maximum Longitude
- 180
- Direct Spatial Reference Method
- Raster
- Object Type
- Pixel
- Lines (pixels)
- 23040
- Samples (pixels)
- 46080
- Bit Type
- 16
- Radius A
- 3396190
- Radius C
- 3396190
- Bands
- 1
- Pixel Resolution (meters/pixel)
- 463.0836
- Scale (pixels/degree)
- 128
- Horizontal Coordinate System Units
- Meters
- Map Projection Name
- Simple Cylindrical
- Latitude Type
- Planetocentric
- Longitude Direction
- Positive East
- Longitude Domain
- -180 to 180