Geologic Investigations Series Map I-2785
This map, compiled photogrammetrically from Viking Orbiter stereo image pairs, is part of a series of topographic maps of areas of special scientific interest on Mars. MTM 500k –15/337E OMKT: Abbreviation for Mars Transverse Mercator; 1:500,000 series; center of sheet latitude 15° S., longitude 337.5° E. in planetocentric coordinate system (this corresponds to –15/022; latitude 15° S., longitude 22.5° W. in planetographic coordinate system); orthophotomosaic (OM) with color coded (K) topographic contours and nomenclature (T) [Greeley and Batson, 1990].
The figure of Mars used for the computation of the map projection is an oblate spheroid (flattening of 1/176.875) with an equatorial radius of 3396.0 km and a polar radius of 3376.8 km (Kirk and others, 2000). The datum (the 0–km contour line) for elevations is defined as the equipotential surface (gravitational plus rotational) whose average value at the equator is equal to the mean radius as determined by Mars Orbiter Laser Altimeter (Smith and others, 2001).
The image base for this map employs Viking Orbiter images from orbit 651. An orthophotomosaic was created on the digital photogrammetric workstation using the DTM compiled from stereo models. Integrated Software for Imagers and Spectrometers (ISIS) (Torson and Becker, 1997) provided the software to project the orthophotomosaic into the Transverse Mercator Projection.
First posted April 4, 2003
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Geological Survey (U.S.), 2003, Topographic Map of the Northwest Loire Valles Region of Mars MTM 500k -15/337E OMKT: U.S. Geological Survey Geologic Investigations Map I-2785, 1 plate, https://pubs.usgs.gov/imap/2785/.