I have another problem for this vegetation index,any body can help me? I so many times write this equation, but has a problem. Could you helping me? I have original on the paper you can see, I attached. How about this vegetation index GEMI: Global Environmental Monitoring Index? How can write this expression? How can write this expression? Just I write so many times this expression; 2*((float(B4)^2-(float(B3)^2))+(1.5*float(B4))+0.5*float(B3))/((float(B4)+float(B3)+0.5))*(1-0.25*(2*(float(B4)^2-float(B3)^2)+(1.5*float(B4)+0.5*float(B3))/(float(B4)+float(B3)+0.5))-(float(B3)-0.125)/(1-float(B3))) Thank you Sincerely Yours Hadi