Hello, I am using ENVI_SVM_DOIT want to ignore some region while using ENVI SVM classifier(or ENVI_SVM_DOIT), so I set the values of these pixels to NaN. But it didn't work, the SVM classifier still classified those pixels. Would it possible to ignore some region in this classifier? Any help would be nice, thank you very much. ==== Well I think I have figured it out. Thank you all the same.