Daily Global Ionosphere Maps GIM-TEC of total electron content 
produced from JPL GPS TEC IONEX MAP                         
TEC values in TECU/10. 
0, 1, ... , 23 Hours, UT.    
Geographic coordinates:                       
   87.5 -87.5  2.5    LAT1/ LAT2/ DLAT	     
 -180.0 180.0  5.0    LON1/ LON2/ DLON