This mosaic is made with computer enhanced Mariner 9 pictures, rectified and scaled to a Lambert conformal projection. Computer processing was performed by the Image Processing Laboratory (IPL) of the Jet Propulsion Laboratory (JPL). Processing included contrast enhancement and high-pass filtering which accentuates topographic features while subduing albedo variations. Photographic reproductions of the images were generated from the IPL digital magnetic tapes and mosaicked by the U.S. Geological Survey.
Relative horizontal placement of pictures is control led by spacecraft tracking data, with adjustment to fit the Mariner 9 control net of August, 1972 (Davies, M.E., 1972, Mariner 9 control net of Mars: August, 1972: Rand Corp ., R-1122-JPL) where possible. Individual analytical adjustment of pictures was not performed. Triangles are shown at the correct latitude and longitude of the control points identified and numbered by Davies (ibid.). Broken crosses are used to identify the images of the control points. Standard deviation of image placement discrepancy is less than 5 km. The projection is based on a theoretical dynamical ellipticity of 1/192. The scale is based on an equatorial radius of 3393.4 km.
