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Elpitha Howington-Kraus

Publications and source records attributed to Elpitha Howington-Kraus.

30 records · Page 2Linked to original sources
USGS2002

Observations of comet 19P/Borrelly by the miniature integrated camera and spectrometer aboard deep space 1

The nucleus of the Jupiter-family comet 19P/Borrelly was closely observed by the Miniature Integrated Camera and Spectrometer aboard the Deep Space 1 spacecraft on 22 September 2001. The 8-kilometer-long body is highly variegated on a scale of 200 meters, exhibiting large albedo variations (0.01 to 0.03) and complex geologic relationships. Short-wavelength infrared spectra (1.3 to 2.6 micrometers) show a slope toward the red and a hot, dry surface (≤345 kelvin, with no trace of water ice or hydrated minerals), consistent with ∼10% or less of the surface actively sublimating. Borrelly's coma exhibits two types of dust features: fans and highly collimated jets. At encounter, the near-nucleus coma was dominated by a prominent dust jet that resolved into at least three smaller jets emanating from a broad basin in the middle of the nucleus. Because the major dust jet remained fixed in orientation, it is evidently aligned near the rotation axis of the nucleus.

Science↗
USGS2002

USGS and DLR topographic mapping of Comet Borrelly

In the fall of 2001, NASA's Deep Space 1 (DS1) probe imaged Comet Borrelly during a flyby encounter. Three of the Borrelly images have geometry suitable to photogrammetrically map the nucleus, which form two stereopairs with an expected precision (EP) of ~410 m and ~670 m each. DS1 team members at the USGS and DLR have independently produced digital elevation models (DEMs) of Borrelly. Automatic stereo-matching algorithms were used by both USGS and DLR, but the USGS DEM was additionally manually edited in stereo. We accomplished a quantitative statistical comparison of the DEMs and found they have a standard deviation of 120 m, which is small compared to the EP above. There are systematic differences, we estimate the stereomatching error to only 0.20 pixel RMS, which is similar to the level of subpixel matching accuracy obtained in a wide variety of other mapping situations. The resulting DEMs enable a variety of applications such as perspective views, photometric modeling and studies of the energy balance of the nucleus. We hope to use the USGS DEM as a starting point to extrapolate the shape of the hidden side of the nucleus. This would not only let us determine the volume and moments of inertia of the nucleus, but would lead to a calculation of the insolation onto the nucleus averaged over an entire orbit, and thence to a model of the evolution of nuclear shape.

Conference Paper↗
USGS2002

USGS high resolution topo-mapping of Mars with Mars Orbiter Camera Narrow-Angle images

We describe our initial experiences producing controlled digital elevation models (DEMs) of Mars with horizontal resolutions of ≤10 m and vertical precisions of ≤2 m. Such models are of intense interest at all phases of Mars exploration and scientific investigation, from the selection of safe landing sites to the quantitative analysis of the morphologic record of surface processes. Topomapping with a resolution adequate to address many of these issues has only become possible with the success of the Mars Global Surveyor (MGS) mission. The Mars Orbiter Laser Altimeter (MOLA) on MGS mapped the planet globally with absolute accuracies <10 m vertically and ~100 m horizontally but relatively sparse sampling (300 m along track, with gaps of >1 km between tracks common at low latitudes). We rely on the MOLA data as the best available source of control and process images from the narrow-angle Mars Orbiter Camera (MOC-NA) with stereo and photoclinometric (shape-from-shading) techniques to produce DEMs with significantly better horizontal resolution. The techniques described here enable mapping not only with MOC but also with the high-resolution cameras (Mars Express HRSC, Mars Reconnaissance Orbiter HiRISE) that will orbit Mars in the next several years.

Conference Paper↗
USGS2001

Utilizing Mars Digital Image Model (MDIM) and Mars Orbiter laser Altimeter (MOLA) data for photogrammetric control

The USGS is producing digital elevation models (DEM) and topographic maps of Mars at scales of 1:250,000 to 1:1,000,000. The initial source material will be Viking Orbiter images, with a later transition to Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) when stereo coverage from that source is available for topographic mapping. The digital terrain models and topographic maps produced by this effort will support geologic mapping and geophysical studies. The maps will be based on the horizontal and vertical control from Mars Orbiter Laser Altimeter (MOLA). Currently, the maps are based on planetographic coordinates, but eventually planetocentric coordinates will be used.

Conference Paper↗
USGS2001

Combining lunar photogrammetric topographic data with Clementine LIDAR data

During the Clementine Mission both oblique and vertical multispectral images were collected. The oblique and vertical images from a single spectral band collected during the same orbit form a stereo pair that can be used to derive the topography. These stereo pairs were used to derive the topography of an area surrounding the lunar South Pole (90°S - 64°S latitude) and North Pole (90°N - 64°N latitude). In addition, during the Clementine mission laser altimeter data were collected. A goal was to match the photogrammetric topographic data to the topographic data collected by the laser altimeter. This required developing some innovative techniques to deal with mismatches between the photogrammetric topographic data set and the laser altimetry topographic data.

Conference Paper↗
USGS2001

High resolution digital elevation models of Mars from MOC Narrow Angle stereoimages

In this abstract we report on our initial experiences performing stereotopographic mapping of Mars with high-resolution images from the Mars Global Surveyor Mars Orbiter Camera Narrow-Angle subsystem (MGS MOC-NA; [1]). Accurate topographic information, and, in particular, high-resolution digital elevation models (DEMs) are of intense interest at all phases of Mars exploration and scientific investigation, from landing site selection to the quantitative analysis of the morphologic record of surface processes.

Conference Paper↗
USGS2001

Validation of the USGS sensor model for topographic mapping of Venus using Magellan radar stereoimagery

The Magellan spacecraft went into Venus orbit in 1990 and by 1992 had made three complete cycles of polar orbits, each cycle covering the full range of longitudes. During this time the spacecraft obtained synthetic aperture radar (SAR) images of >96% of the planet at a resolution of 75 m/pixel. Images taken with a decreased look angle from vertical, primarily during Cycle 3, provide stereo coverage of 17% of the planet when combined with images with same-side illumination from earlier in the mission. The stereo geometry of these images is extremely favorable, allowing elevation measurements with an estimated vertical precision (EP) of ~10 m. Magellan also obtained radar altimetry data at a horizontal resolution of 10x25 km, but photogrammetric analysis of the stereoimagery can yield topographic maps with a horizontal resolution more than an order of magnitude superior to that of the altimeter.

Conference Paper↗
USGS2001

Lunar orbiter digitization and cartographic processing

Digitization and cartographic processing of 5 Lunar Orbiter (LO) IV frames (109H, 110H, 114H, 115H, and 114M) are now complete, and these data are available online at http://wwwflag.wr.usgs.gov/USGSFlag/Space/LunarOrbiter/lunorbWebtop.html. Coverage ofthese data extends from Eratosthenes crater on the west to Mare Serenitatis in the east, and from Aristoteles crater in the north to Rima Hyginus in the south. Geologic features in this area encompass a wide variety of lunar units, processes, and ages, and they include parts of the Apennine Mountains, the KREEP-rich Apennine Bench Formation, Rima Bode pyroclastics (Figure 1), Mare Vaporum, Sulpicius Gallus, and the Imbrium basin ejecta southeast of the basin rim. These data products demonstrate our capability for digitizing and cartographically processing the LO data.

Conference Paper↗
USGS2001

Planetary geodesy and cartography at the USGS, Flagstaff: Moon, Mars, Venus, and beyond

An important theme of our work is the synergistic use of a variety of geodetic, cartographic, and photogrammetric software packages. The USGS digital cartographic software system ISIS provides most of the processing capability needed for planimetric mapping tasks such as our revision of the global digital image mosaic of Mars (MDIM). The geodetic control network on which this mosaic is based was produced at RAND with planetary bundle-block adjustment software that was developed there and that has recently been transferred to the USGS where we are also using it to compute a revised control network of Io from Voyager and Galileo images. The revised MDIM compiled in 2000 is substantially improved over the version produced from the same ~4500 Viking Orbiter images in 1991, both in geodetic accuracy and in radiometric/cosmetic quality. Maps of the Galilean satellites of Jupiter have also been improved geodetically and cosmetically as we have added Galileo images to the control networks and digital mosaics. Stereotopographic mapping of the Moon, Mars, Venus, and the asteroid Eros requires ISIS for data ingestion and calibration steps, along with the commercial photogrammetric software SOCET SETâ for “photogrammetric” steps such as adjustment of control and topographic model extraction and editing. Novel procedures must frequently be developed to deal with problems of planetary datasets such as the need to use large numbers of small images, nonuniform image coverage, poor image overlap, and lack of true ground control. Some sensors, such as the Magellan Synthetic Aperture Radar (SAR) and Mars Global Surveyor Mars Orbiter Camera (MOC), also require the development of specialized sensor model software. A second important theme is the complementarity between photogrammetric techniques and the laser altimeter systems coming into increasing use on planetary spacecraft. Stereoanalysis of Clementine images of the Moon has been used to fill in major gaps in the altimeter dataset at high latitudes, but the stereo data must be tied to the altimetry where the datasets overlap. For Mars and Eros, our stereomapping provides spatial sampling of topography finer than that achieved by altimetry, but use of the altimetry data for vertical control is essential to improve the absolute accuracy of photogrammetric topographic models. The dense spatial sampling of the Mars Orbiter Laser Altimeter (MOLA) dataset makes it useful as a source of horizontal control as well: features in images can easily be recognized in the altimetry and can be assigned coordinates with such small uncertainties that they function effectively as ground control points in the photogrammetric bundle-block adjustment. Such MOLA-derived ground points will be used to further improve the Viking Orbiter based control network and MDIM late in 2001 and will be incorporated into a subsequent network and mosaic based on global stereo imagery from MOC.

Conference Paper↗
USGS2000

Recent planetary topographic mapping at the USGS, Flagstaff: Moon, Mars, Venus, and beyond

We are currently using stereophotogrammetric techniques to compile digital topographic models of parts of the Moon, Mars, Venus, and the asteroid Eros in support of the NASA program of planetary exploration. This work requires the synergistic use of the USGS digital cartographic software system ISIS for data ingestion and calibration steps, along with the commercial software SOCET SET for “photogrammetric” steps such as adjustment of control and topographic model extraction and editing. Novel procedures must frequently be developed to deal with problems of planetary datasets such as the need to use large numbers of small images, nonuniform image coverage, poor image overlap, and lack of true ground control. Some sensors, such as the Magellan Synthetic Aperture Radar, also require the development of specialized sensor model software. An important theme of our work is the complementarity between photogrammetric techniques and the laser altimeter systems coming into increasing use on planetary spacecraft. Stereoanalysis of Clementine images of the Moon has been used to fill in major gaps in the altimeter dataset at high latitudes, but the stereo data must be tied to the altimetry where the datasets overlap. For Mars and Eros, our stereomapping provides spatial sampling of topography finer than that achieved by altimetry, but use of the altimetry data for vertical control can significantly improve the absolute accuracy of photogrammetric topographic models.

Conference Paper↗
USGS1999

Digital mapping of the Mars Pathfinder landing site: Design, acquisition, and derivation of cartographic products for science applications

The Imager for Mars Pathfinder (IMP) acquired more than 16,000 images and provided panoramic views of the surface of Mars at the Mars Pathfinder landing site in Ares Vallis. This paper describes the stereoscopic, multispectral IMP imaging sequences and focuses on their use for digital mapping of the landing site and for deriving cartographic products to support science applications of these data. Two‐dimensional cartographic processing of IMP data, as performed via techniques and specialized software developed for ISIS (the U.S. Geological Survey image processing software package), is emphasized. Cartographic processing of IMP data includes ingestion, radiometric correction, establishment of geometric control, coregistration of multiple bands, reprojection, and mosaicking. Photogrammetric processing, an integral part of this cartographic work which utilizes the three‐dimensional character of the IMP data, supplements standard processing with geometric control and topographic information [ Kirk et al. , this issue]. Both cartographic and photogrammetric processing are required for producing seamless image mosaics and for coregistering the multispectral IMP data. Final, controlled IMP cartographic products include spectral cubes, panoramic (360° azimuthal coverage) and planimetric (top view) maps, and topographic data, to be archived on four CD‐ROM volumes. Uncontrolled and semicontrolled versions of these products were used to support geologic characterization of the landing site during the nominal and extended missions. Controlled products have allowed determination of the topography of the landing site and environs out to ∼60 m, and these data have been used to unravel the history of large‐ and small‐scale geologic processes which shaped the observed landing site. We conclude by summarizing several lessons learned from cartographic processing of IMP data.

Journal of Geophysical Research E: Planets↗