Inasmuch as multiringed basins occur widely on that part of Mercury photographed by Mariner 10, as well as on the Moon and Mars, they offer a potentially valuable basis for comparison between these planetary bodies. Map units are distinguished on the basis of topography, texture, and albedo and are ranked in relative age on the basis of superposition and transection relations, density of superposed craters, and sharpness of topography. Because of the lack of a widespread, easily identifiable stratigraphic datum on this part of Mercury, a morphologic classification of crater and basin materials was the basis for determining relative ages of many materials. A photomosaic map of the best available photographs aided greatly in geologic interpretation and mapping. All attributes created during the creation process were verified by displaying the lines in both the database and the spatial coverage, but no formal tests were performed.
Line geometry is topologically clean.
Information has been obtained from sources believed to be reliable, but its accuracy and completeness and the opinions based thereon, are not guaranteed. As every effort is made to provide accurate information in this database, USGS would appreciate it if users could call to our attention any errors that may occur by communicating with the contact person.