Terms of Reference

• Status and technical definition of coordinate systems and geodetic control networks for mapping of planets and satellites
• Documentation of basic spacecraft datasets for extraterrestrial mapping, current and planned extraterrestrial mapmaking activities, and planetary cartographic products
• Development and documentation of new techniques for data acquisition and extraterrestrial mapping
• Development of GIS applications to support extraterrestrial exploration and science
• Web-based delivery of extraterrestrial map products and GIS data
• Cooperation with related working groups from ICA, IAU, NASA, and ESA

2002 Annual Report

Planetary Mission Highlights

NASA's Mars 2001 Odyssey spacecraft began its investigation in February of 2002. Noteworthy from a mapping perspective is the Thermal Emission Imaging System (THEMIS), which includes a 5-band, 18-m/pixel visible imaging system and a 10-band, 100-m/pixel thermal infrared imager. The infrared imager, the first of its kind to map Mars, is capable of operating at night as well as during the day and is providing new kinds of information about surface composition, texture, and thermal properties. The first release of archived image data was made in October, with subsequent releases to follow at 3-month intervals. At present, THEMIS observations are primarily directed to examining potential landing sites and other targets of high scientific interest, but the instrument has the potential to provide global or near-global coverage of Mars that could be used for systematic mapping at 100 and 18-m resolutions (compared to ~200 m for the best current image maps of the planet). Stereo imaging is also a possibility; mission operation rules currently preclude turning the spacecraft off-nadir, but these rules may be relaxed in the future, and combination of THEMIS data with existing off-nadir images is also possible.

Preparation of the ESA Mars Express orbiter and the two NASA Mars Exploration Rovers (MER) for launch in the second quarter of 2003 continues successfully and on schedule. Mars Express will carry (in addition to other instruments and the Beagle 2 lander) the High-Resolution Stereo Camera, a 9-line pushbroom system that will obtain high resolution stereo and color coverage over an unprecedentedly large fraction of the red planet. The MER rovers will carry multiple stereo imaging systems as well as a microscopic imager and several spectroscopic instruments, and will be capable of traveling hundreds of meters during a 90-day nominal mission. Selection of safe and scientifically interesting landing sites for the rovers has been a major focus of NASA activity in 2002, with a final decision expected early in 2003. High-resolution topographic mapping of potential landing sites by Working Group Chair Randy Kirk and others, using stereo and shape-from-shading analysis of Mars Global Surveyor Mars Orbiter Camera images has played an important role in assessing the risks for landing and rover operations. Collection and analysis of stereo and other images of the sites finally selected will continue in 2003, with the emphasis turning to planning of rover operations. A key participant in this planning will be Working Group member Ron Li, who was selected as a MER Participating Scientist in May 2002.

Accomplishments

The Working Group sponsored a session on Extraterrestrial Mapping at the ISPRS Commission IV Symposium held in Ottawa in July. Five oral presentations on aspects of Mars photogrammetry and cartography were offered, one of which, on high-resolution topographic mapping, was included in the Plenary Session of the Symposium. In addition, a poster contribution described stereomapping of the nucleus of Comet Borrelly by teams in the US and Germany. All papers were greeted warmly and attentively by the audience and the session was judged a success by its participants.

Though not an ISPRS function, a session at the fall meeting of the American Geophysical Union in December deserves mention here because it commemorated the career of former Working Group member Merton E. Davies, who died in 2001. In a 50-year career at RAND, Davies was one of the pioneers of both satellite surveillance of the Earth and spacecraft imaging of the planets. He participated in missions to every planet except Pluto and was responsible for constructing geodetic control networks of bodies from Mercury to Neptune's satellite Triton. Mert was also a man of exceptional warmth, gentleness, and joy for life, a mentor, and a friend. He is profoundly missed by all who had the pleasure of knowing him.

Work on the Extraterrestrial Mapping website hosted by the USGS, Flagstaff, at astrogeology.usgs.gov/Projects/ISPRS/ continues slowly but steadily as dictated by available funding. In 2002 the site was redesigned to meet U.S. Government requirements for accessibility, and a variety of new datasets were added.

Future Plans

Plans for a Workshop on "Advances in Planetary Mapping 2003" sponsored by the Working Group have been underway for some time and were recently announced. The Workshop will be held at the Lunar and Planetary Institute in Houston on 22 March 2003, immediately after the conclusion of the XXXIVth Lunar and Planetary Science Conference. The due date for submission of abstracts for the Workshop is 21 January. Additional information about the Workshop can be found at wwwflag.wr.usgs.gov/USGSFlag/Space/Isprs/MEETINGS/Houston2003/index2003.html. For more information on Lunar and Planetary Science Conference, see www.lpi.usra.edu/meetings/lpsc2003/. Abstracts accepted for the Workshop will be posted on the Working Group website, which will also continue to be updated with new planetary datasets and short tutorials on aspects of planetary mapping throughout the coming year.

2001 Annual Report

Planetary Mission Highlights

The past year has seen the completion of several unprecedented datasets for extraterrestrial mapping and the initiation of plans that will result in even more spectacular observations in the coming half-decade. In February 2001, the NEAR-Shoemaker spacecraft ended its one-year exploration of asteroid 433 Eros by obtaining images with centimeter resolution and then gently landing on the surface. Over the course of the mission, 160,000 images were returned, permitting the Multispectral Imager team to construct a highly detailed digital shape model and global image mosaics. Many of the highest resolution images, including significant stereo coverage, have yet to be exploited for mapping. The NEAR Laser Rangefinder obtained global ranging data that provide an independent estimate of the shape of Eros and elucidate small-scale topographic features. In contrast with the lengthy NEAR mission, the September flyby of comet Borrelly by the Deep Space 1 probe was over in a matter of minutes, but the MICAS imager on board succeeded in obtaining images of the 8-km-long nucleus with resolutions as good as 50 m and excellent stereo convergence. These images support not only geologic interpretation but also first-ever quantitative topographic mapping of a comet nucleus.

The Mars Global Surveyor spacecraft completed its primary mission in January and entered an extended mission phase, one of the main goals of which is for the Mars Orbiter Camera to obtain numerous high-resolution (1.5 to 3 m/pixel) images, including stereo coverage, of candidate landing sites for the 2003 Mars Exploration Rovers. In June, the Mars Orbiter Laser Altimeter (MOLA) ceased mapping after obtaining 640 million measurements of the martian surface and atmosphere. The absolute accuracy of the MOLA dataset, after a global adjustment based on orbit track crossings, is believed to be <10 m vertically and ~100 m horizontally, making it the primary standard for martian geodetic control for the foreseeable future. Mapping Scientists should expect plenty of high-resolution images to tie to this control. In early November, the 2001 Mars Odyssey spacecraft successfully entered orbit and tested its THEMIS camera, which will image a large fraction of the planet with up to 18 m/pixel resolution in several visible wavelengths and obtain global infrared imagery at 100 m/pixel. Also in November, NASA announced the selection of the HiRISE camera for its 2005 Mars Reconnaissance Orbiter. This instrument is intended to combine ultrahigh resolution (0.25-0.5 m/pixel) with large image size (typically 20,000x40,000 pixels). Like the Mars Orbiter Camera, it will be pointed off-nadir part of the time to permit stereomapping.

Accomplishments

The major event planned by the Working Group in 2001 was a Workshop/Symposium on "Planetary Mapping 2001" to be held at the U.S. Geological Survey facility in Flagstaff, Arizona in mid-October. The title expresses the deliberate broadening of scope compared to past "Mapping of Mars" workshops, in part because of the extraordinary success of the NEAR mission. In addition to oral and poster sessions, the two-day workshop was to include a roundtable discussion on mappers' needs for orientation data and related software, led by Chuck Acton of NASA's Navigation Ancillary Information Facility (NAIF). A half-day excursion to Meteor Crater (an exceptionally well preserved 1.6-km-diameter impact crater east of Flagstaff) after the workshop was to be led by Dr. David Roddy (USGS), a noted authority on the crater. As of early September, approximately 20 presentations had been promised, with additional colleagues from around the U.S. and Europe indicating that they would attend the workshop to hear the talks.

Unfortunately, in the wake of the September 11 terrorist attacks, restrictive travel policies and conflicts with other meetings being rescheduled forced a majority of speakers to cancel their plans to attend the workshop. The WG considered rescheduling the event, but could not find a suitable date given the many other scheduled (and rescheduled) meetings in the fall quarter. The workshop was therefore cancelled as a physical meeting, but participants were invited to share their research through a "virtual workshop" to be hosted on the WG website (http://wwwflag.wr.usgs.gov/USGSFlag/Space/Isprs/index.html; follow the "Meetings" link). Authors who had contributed short abstracts for the meeting were invited to expand these into mini-papers and/or to supply electronic presentations. Contributions received by the end of November will be included on the site shortly thereafter. The workshop authors were also strongly encouraged to report on their research in an Extraterrestrial Mapping session at the 2002 Commission Symposium.

A particularly significant paper submitted to the workshop by Thomas Duxbury (JPL) and colleagues concerns efforts of the NASA Mars Geodesy/Cartography Working Group chaired by Duxbury to determine authoritative values of cartographic constants for Mars. Members of the NASA group (which has considerable overlap with the ISPRS WG) used Mars Global Surveyor MOC and MOLA data to define a reference ellipsoid and prime meridian for Mars with uncertainties of a few hundred meters or less. They also recommend the use of previously published rotational parameters based on tracking of the Viking and Mars Pathfinder landers. All of these parameter estimates, which have been transmitted to the International Astronomical Union (IAU) and will appear in the forthcoming report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites, are unlikely to be superseded in the coming decade. Finally, the NASA WG strongly recommends the use of planetocentric latitude and east longitude as a single coordinate system for future Mars cartographic products. This recommendation is currently under review by NASA.

WG Chair Randy Kirk attended the International Cartographic Congress in Beijing in August and delivered a paper in the planetary mapping session on current USGS efforts to revise the control networks and global maps of Mars and the Galilean satellites of Jupiter, including the suggestions for Mars cartographic coordinates and coordinate system just described. In discussions with the International Cartographic Association Commission on Planetary Mapping, chaired by Dr. Kira Shingareva (Moscow State University), Kirk renewed the agreement to pursue joint activities of the ICA Commission and the ISPRS WG. A glossary of planetary mapping terms is now partly completed, with the ICA members supplying definitions of planetary geologic terms that may be new to cartographers and the WG to define cartographic and photogrammetric terms for geologists. When complete, this material will also be added to the WG website.

Future Plans

An extensive revision of the ISPRS-ET website has already started and is the main activity planned for the near future. The USGS has taken primary responsibility for maintenance of the site, so that the URL given above is now the primary site; reestablishment of a European mirror site at the University College London is planned for the near future. We have begun the long-anticipated creation of an archive of planetary DEMs and orthophotomosaics on the site (follow the "Products" link), starting with a series of USGS 1:500,000-scale topographic maps of Mars compiled from Viking Orbiter imagery. A substantial backlog of USGS and other Mars DTMs at a variety of scales will follow, as well as maps of the Moon and Venus. We will also be redesigning the site to comply with U.S. Government accessibility requirements, and adding links to other sites relevant to the Working Group, such as the Planetary Interactive GIS-on-the-Web Analyzable Database (PIGWAD) at http://webgis.wr.usgs.gov.

2000 Annual Report

The WG organized a session on Extraterrestrial Mapping at the XIXth Congress of the ISPRS, held in Amsterdam, 16-23 July 2000. Randolph Kirk of the USGS gave an overview of "Recent planetary topographic mapping at the USGS, Flagstaff: Moon, Mars, Venus, and Beyond." The role of Mars Orbiter Laser Altimeter (MOLA) data in Mars geodesy and cartography was addressed by two papers, "Automated MOLA track registration in MOC and Viking images and its application for the establishment of new 3-D control points on Mars," by Jung-Rack Kim (UCL), and "Controlled topographic image mosaics from combination of Viking Orbiter images and Mars Orbiter Laser Altimeter data" presented by Juergen Oberst (DLR). Wolfgang Zeitler of DLR presented results on "Photogrammetric point determination using digital Galileo SSI images from Asteroid Ida" and the session concluded with a paper on "Large scale Mars mapping and rover localization using descent and rover imagery" by Rongxing Li (OSU). The session was well-attended and generated lively discussion of all of the papers in the intervals needed to connect each speaker's laptop to the digital projection system.

A Workshop/Symposium "Planetary Mapping 2001" is being planned (see announcement on the Meetings page of this website). This workshop will be held at the U.S. Geological Survey in Flagstaff, Arizona, 18-19 October 2001. Reports on Mars mapping, which have been the exclusive focus of past workshops, will be welcome but we also anticipate significant new results on the mapping of the satellites of Jupiter with Galileo data and of the asteroid 433 Eros with Near Earth Asteroid Rendezvous mission data. The workshop will be followed by an optional half-day fieldtrip to Meteor Crater, the best-preserved impact structure on Earth.

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