Hi there, I was wondering, do you have access to ENVI + IDL License?, if you do, I think you can open the MODIS file in ENVI: File ? Open External File ? EOS ? MODIS And then you can export the variable of that image into IDL. To export IDL variables: From the ENVI main menu bar, select File ? Export to an IDL Variable. The Export to IDL Input File/Band dialog displays. Select an input file or band. In the Export Variable Name dialog, select one of the following options: If the variable was previously defined, select on the name in the Select variable to receive export list. If the variable is a new one, enter the name of an undefined IDL variable in the New Variable Name field. Click OK. The exported data is available to use at the ENVI / IDL command line. Cheers,   Fernando