How do I get to separate snow and cloud usng ENVI in CHris data?I tried the Snow index and did (b3-b18)/(b3+b18)...but the result was not a binary one. Since this CHRIS data only has wavelenght range from 0.4 to 1.05 microns...it has been giving me a hassle. I wish i could do something with this data. anyone..please help me. Peg..?