Mars Global Surveyor (MGS) MAG/ER Derived Field Map of Mars Data Description  
MAG - Magnetometer                                                            
ER - Electron Reflectometer                                                   
                                                                              
  PDS3 DATA_SET_ID               = MGS-M-ER-5-FIELD-MAP-V1.0                  
  ORIGINAL DATA_SET_NAME         = MGS MARS ER 5 FIELD MAP V1.0               
  START_TIME                     = N/A                                        
  STOP_TIME                      = N/A                                        
  DATA_SET_RELEASE_DATE          = 2010-08-05                                 
  PRODUCER_FULL_NAME             = DR. ROBERT J. LILLIS                       
                                                                              
  ====================================================================        
  Collection 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.