Sorry, the following is more an answer than a response: I understand that each rule image (one by class) shows the probability of pixel belonging to class. So we can expect a value between 0 and 1 and the sum of all the probabilities for each pixel will be one. However when I look at the values of the pixels in rule image (produced by maximum likelihodd) I get negative values. I saw that you posted your question 2 months ago, about max. likelihood rule images. Do you know some way to interpret rule images ? Best Regards, JF

sorry, in my last message I was wrong. For the Maximum Likelihood Classification, ENVI calculates the discriminant functions for each pixel gi(x). The probability is gi(x)/(sum over i of all gi(x)). So it seems that using tools as "math band" it is possible to calculate the probabilities (or exporting to some other package such as grid in arc/info to carry the computing of the probabilities. There is more detauils in http://www.rsinc.com/serv...asp?ttid=1793&pv=yes