As we all know, the tasseled cap transformation in ENVI only output three bands, the brightness, greenness and third. The results, however, is quite different from erdas. The erdas using the following coefficients: soil brightness 0.2909 0.2493 0.4806 0.5568 0.4438 0.1706 10.3695 greeness –0.2728 –0.2174 –0.5508 0.7221 0.0733 –0.1648 –0.7310 wetness 0.1446 0.1761 0.3322 0.3396 –0.6210 –0.4186 –3.3828 haze 0.8461 –0.0731 –0.4640 –0.0032 –0.0492 0.0119 0.7879 TC5 0.0549 –0.0232 0.0339 –0.1937 0.4162 –0.7823 –2.4750 TC6 0.1186 –0.8069 0.4094 0.0571 –0.0228 0.022 –0.0336 this coefficients was described in this book(P205). Title: Remote Sensing: Models and Methods for Image Processing Author: Schowengerdt, R. A. Source: 2006, 3 ed, Academic Press, 515 p I don't know what coefficients were used by envi, and sometime is quite inconvenient when I want to get the wetness component.