In nanoscope analysis software which is used to analyse AFM images is having PSD determination facility. The PSD (power spectral analysis) plot which comes is in liear scale in X and Y axes which is not understood properly and if also we are exporting the data and plot it in origin or other graph plotting software making Logarithmic scale then the expectation plots find to be horrible. If some regularity in the features are there or any wavelength is there it is showing wrong expectation with visual characterization and also manual measurement.