ENVI has a utility called the "Map Coordinate Converter" that can be used to accomplish this task. You can use this utility interactively using the GUI interface within ENVI or programmatically within IDL : IDL> ENVI,/RESTORE_BASE_SAVE_FILES IDL> ENVI_BATCH_INIT IDL> iProj=ENVI_PROJ_CREATE(/geographic) IDL> oProj=ENVI_PROJ_CREATE(/utm,zone=13) IDL> iXMap = -105 IDL> iYMap = 40 IDL> ENVI_CONVERT_PROJECTION_COORDINATES, iXMap, iYMap, iProj, oXMap, oYMap, oProj IDL> help, oXMap[0], oYMap[0] DOUBLE = 500049.12 DOUBLE = 4427548.5 Of course, you need to have ENVI installed with IDL for this to work.