Data Set Overview ----------------- The electron reflectometry map of Mars consists of an ASCII file with latitude and longitude in bins of 0.5 deg. This map is a derived data product; a number of assumptions went into its creation. For details, please consult the following paper: An improved crustal magnetic field map of Mars from electron reflectometry: Highland volcano magmatic history and the end of the martian dynamo Robert J. Lillis, Herbert V. Frey, Michael Manga, David L. Mitchell, Robert P. Lin, Mario H. Acuna, Stephen W. Bougher Icarus 194 (2008) 575-596 doi:10.1016/j.icarus.2007.09.032 (To access the paper, go to the DOI website at http://dx.doi.org and type in the above DOI.) The ASCII map file in this data set is the same one used in the above cited paper. Data ---- The contents of the map file are the elements of a 720 x 360-element matrix, i.e. 720 rows and 360 columns. The spacing is 0.5 deg in both latitude and longitude. The values of latitude are: -89.75 deg, -89.25 deg, -88.75 deg,...... -0.25 deg, 0.25 deg,..., 88.75 deg, 89.25 deg, 89.75 deg. The longitudes are EAST longitudes and, from right to left, are: 0.25 deg, 0.75 deg, 1.25 deg,..., 358.75 deg, 359.25 deg, 359.75 deg. In the file, the elements of the matrix are grouped into rows of six values each.

Confidence Level Overview ------------------------- IMPORTANT NOTE: ER-derived magnetic field magnitudes are NOT the same as magnetometer data and should NOT be treated as such. Users of the data are strongly advised to contact Dr. Robert J. Lillis, the provider of the map, before using the data in publications.