I have written an equation for plotting the load power contour of RF power amplifier in data display window. The function is used "" contour() "" to plot the power. This function is giving an error that the 1st argument of the function, which is the load power in dBm, is a surface data and it is unable to contour the surface, an invalid surface problem occurs. So can anyone suggest me how to solve this problem of surface data? I have also used the function ""contour_ex"". It is also of no use.