Hello everybody, I actually have a similar problem. I have Landsat ETM images that should be transformed via tasseled cap. Besides I already calculated the surface reflectance. Now I have three possibilities:   1) Applying the Landsat 7 at-satellite reflectance coefficients in combination with the surface reflectance data    IS THAT VALID? 2) Calculate the at- satellite reflectance and then use the Landsat 7 coefficients 3) Use the surface reflectance values in combination with the coefficients developed by Christ of Landsat TM surface reflectance   What will be the best solution? Many thanks for your help! Sarina