Preliminary geologic map of the Memnonia quadrangle of Mars, Viking Mars 1975 landing site

This mosaic is made with computer-enhanced, unrectified Mariner 9 pictures provided by The Jet Propulsion Laboratory Mission and Test Video System (MTVS). The Vertical Automatic Gain Control (Vert. AGC) version is used. The pictures were scaled for a "best fit" by the U.S. Geological Survey using spacecraft tracking data. Discrepancies between image positions are as large as one degree in latitude and longitude.