You can use ENVI API to convert those files. For example, to convert all TIFF files in a folder to ENVI format, you can use the script below: e = envi() root = Dialog_Pickfile(/DIRECTORY) files = File_Search(root + '*.tif', COUNT=nFiles) rasters = ObjArr(nFiles) for i = 0L, nFiles-1 do begin rasters[i] = e.OpenRaster(files[i]) rasters[i].Export, e.GetTemporaryFilename(), 'ENVI' endfor -Xiaoying

Hmmm been tinkering with this for hours and still get this same result with the above code: % Attempt to subscript FILES with I is out of range. % Execution halted at: $MAIN$ % Attempt to subscript RASTERS with I is out of range. % Execution halted at: $MAIN$ The code listed was very similar to that I was trying to write myself, and I got similar error messages. Any ideas?

Sounds like IDL isn't liking the value of i at some point during the looping. You may want to add some PRINT statements to check the value of nFiles before you start that loop. Maybe you are ending up with a situation where no files are found? - Peg Exelis VIS