atcorr is supposed to be run under Grass GIS. The following steps needs to be taken to compile and use it under Grass. Sorry that there is not automatic script to do all this. If you feel this is a big issue you are welcome to donate it. The following steps should be all that is needed: 1. make the binaries ./configure make 2. either create a symbolic link or copy the create binary to where ever grass installed it's binaries. This might need you to have root privilages. The link name must be i.atcorr or else the tcltk will not work. ln -s atcorr/atcorr GRASS_BINARIES/i.atcorr 3. install the tcltk interface for this module. 3.1 Create another symlink for the interface script. ln -s tcltk/i.atcorr GRASS_BINARIES/../tcltk/module/i.atcorr 3.2 Edit the main menu script and place the following 3 lines in GRASS_BINARIES/../tcltk/main/menu.tcl: "Atmospheric corrections (6S)" "" { "source $env(TCLTKGRASSBASE)/module/i.atcorr" } They should be placed in the menu block starting with the line: set image_processing { under the line: -separator Now you are ready to start using it from Grass.