I had a bit of an issue with a radar project I was undertaking: The radar data was brought into ENVI as unsigned integer data, which was fine for doing everything except filtering - when I filter data it turns it into integer data, and then doesn't display properly. If I edit the header data type back to unsigned integer it still won't work. How can I get round this problem? I haven't realy used IDL before so any programming may have to be explained step by step! Also, is there an easy way to convert the data into dB? Thanks