Mars MGS MOLA DEM 463m

Primary Authors

MOLA Team

Originators

Goddard Space Flight Center

Publisher

USGS Astrogeology Science Center

Abstract

Product Information: This digital elevation model (DEM) is based on data from the Mars Orbiter Laser Altimeter (MOLA; Smith et al., 2001), an instrument on NASA's Mars Global Surveyor (MGS) spacecraft (Albee et al., 2001). The MOLA DEM represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann et al., 2001; Neumann, Smith & Zuber, 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 et al., 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 et al., 2001). However, the total elevation uncertainty is at least ±3 m due to the global error in the areoid (±1.8 meters; Neumann et al., 2001) and regional uncertainties in its shape (Neumann, 2002). Pixel resolution is 463 meters per pixel (m). This version is slightly updated from the original PDS (GeoScience Node) MOLA release. (1) The polar gaps from 88 to 90 north and south have been filled by reprojecting polar PDS releases. (2) The radius, still as a sphere, has been updated to conform to the IAU 2000 definition for Mars 3396190.0 m. Mission and Instrument Information: MGS was the first successful U.S. mission launched to Mars since the Viking mission in 1976 (Albee et al., 2001). MGS launched on November 7, 1996 atop a three-stage Delta II launch vehicle from launch pad 17A at Cape Canaveral Air Station, FL. The thirdstage Star 48B solid rocket later propelled the spacecraft out of Earth orbit and on its way to Mars. After a 20-year absence at the planet, MGS ushered in a new era of Mars exploration with its five science investigations (NASA JPL, 2010) MGS arrived at Mars in September 1997 and has contributed a multitude of findings, including signs of past, persistent water such as an ancient delta and currently active water features in the gullies of canyon walls. After nearly a decade of discovery, MGS went silent in November 2006 (NASA JPL, 2010). The MOLA created the most accurate global topographic map of any planet in the solar system, giving scientists elevation maps precise to within about 30 centimeters (1 foot) in the vertical dimension. Data from the laser altimeter identified pathways for the flow of past water and the locations, sizes, and volumes of watersheds. The instrument detected the heights of clouds and identified dynamic features in the atmosphere, such as gravity waves (NASA JPL, 2010). The MOLA showed seasonal changes in the height of the Martian surface (such as snow depth) that represented the first direct global measurement of the amount and distribution of condensed carbon dioxide. In June 2001, part of the laser reached the end of its life, but a sensor continued to detect changes in surface brightness in the near infrared part of the spectrum. These data provided evidence of cloud coverage and atmospheric variations (NASA JPL, 2010). References: Albee, A. L., Arvidson, R. E., Palluconi, F., & Thorpe, T. (2001). Overview of the Mars Global Surveyor mission. Journal of Geophysical Research, 106(E10), 23291-23316. https://doi.org/10.1029/2000JE001306 de Vaucouleurs, G., Davies, M. E., & Sturms Jr., F. M. (1973). Mariner 9 areographic coordinate system. Journal of Geophysical Research, 78, 4395-4404. https://doi.org/10.1029/JB078i020p04395 Duxbury, T. C., Kirk, R. L., Archinal, B. A., & Neumann, G. A. (2002). Mars Geodesy/Cartography Working Group recommendations on Mars cartographic constants and coordinate systems. Paper presented at Joint International Symposium on Geospatial Theory, Processing and Applications: ISPRS Commission IV Proceedings, Working Group 9—Extraterrestrial Mapping, Proceedings, International Society for Photogrammetry and Remote Sensing, Ottawa, Canada. http://www.isprs.org/commission4/proceedings/paper.html Greeley, R., & Batson, R. M. (1990). Planetary mapping (274-275), Cambridge, UK: Cambridge University Press. ISBN 0-521-30774-0 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 of Mars (GMM-2B) from Mars Global Surveyor. Journal of Geophysical Research-Planets, 106(E10), 23359-23376. https://doi.org/10.1029/2000JE001426 National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) (2010). Mars Global Surveyor. https://mars.nasa.gov/mgs/overview/ Neumann, G. A., Rowlands, D. D., Lemoine, F. G., Smith, D. E., & Zuber, M. T. (2001). Crossover analysis of Mars Orbiter Laser Altimeter data. Journal of Geophysical Research, 106(E10), 23753–23768. https://doi.org/10.1029/2000JE001381 Neumann, G. A. (2002). Written communication. Neumann, G. A., Smith, D. E., & Zuber, M. T. (2003). Two Mars years of clouds detected by the Mars Orbiter Laser Altimeter. Journal of Geophysical Research, 108(E4), 5023. https://doi.org/10.1029/2002JE001849 Seidelmann, P. K., Abalakin, V. K. Bursa, M., Davies, M. E., de Bergh, C., Lieske, J. H., Oberst, J., et al. (2002). Report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites 2000. Celestial Mechanics and Dynamical Astronomy, 82, 83-110. https://doi.org/10.1007/s10569-010-9320-4 Smith, D. E., Sjogren, W. L., Tyler, G. L., Balmino, G., Lemoine, F. G., & Konopliv, A. S. (1999). The gravity field of Mars—Results from Mars Global Surveyor. Science, 286, 94-96. https://doi.org/10.1126/science.286.5437.94 Smith, D. E., Zuber, M. T., Frey, H. V., Garvin, J. B., Head, J. W., Muhleman, D. O., Pettengill, G. H., et al. (2001). Mars Orbiter Laser Altimeter Experiment summary after the first year of global mapping of Mars. Journal of Geophysical Research, 106(E10), 23689-23722. https://doi.org/10.1029/2000JE001364 Wessel, P., & Smith, W. H. F. (1998). New, improved version of Generic Mapping Tools released. Eos, Transactions of the American Geophysical Union, 79(47), 579. https://doi.org/10.1029/98EO00426

Purpose

The data from MOLA have been used to create the most accurate topographic map of Mars to date.

Contact and Distribution

Format

Digital Elevation Model, Topographic Map

Access Constraints

Public domain

Access Scope

PDS

Use Constraints

Please cite authors

Series Id

MEGDR

Edition

2003-03-21

Supplemental Information

http://geo.pds.nasa.gov/missions/mgs/megdr.html

Native Data Set Environment

ISIS v3

Astrogeology Theme

Remote Sensing

Online Package Link

https://astrogeology.usgs.gov/search/map/mars_mgs_mola_dem_463m

External File Size

2 GB

Online File Link

https://planetarymaps.usgs.gov/mosaic/Mars_MGS_MOLA_DEM_mosaic_global_463m.tif

Contact Address

2255 N. Gemini Drive

Contact City

Flagstaff

Contact State

AZ

Contact Postal Code

86001

Contact Email

astroweb@usgs.gov

Logical Consistency

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.

Source Title

MOLA Mission Experiment Gridded Data Records (MEGDRs)

Source Online Linkage

http://geo.pds.nasa.gov/missions/mgs/megdr.html

PDS Status

PDS 3 Archived

Attribute Accuracy Report

Best Effort

Horizontal Positional Accuracy Report

Accurate to Control Net

Vertical Positional Accuracy Report

Accurate to Control Net

Geospatial Information

Target

Mars

System

Mars

Minimum Latitude

-90

Maximum Latitude

90

Minimum Longitude

-180

Maximum Longitude

180

Direct Spatial Reference Method

Raster

Object Type

Grid Cell

Raster Row Count (lines)

23040

Raster Column Count (samples)

46080

Bit Type (8, 16, 32)

16

Quad Name

Radius A

3396190

Radius C

3396190

Bands

1

Pixel Resolution (meters/pixel)

463.0835744

Scale (pixels/degree)

128

Map Projection Name

Simple Cylindrical

Latitude Type

Planetocentric

Longitude Direction

Positive East

Longitude Domain

-180 to 180