2D FFT and the frequency or scale from a 2D spatial series

Hello, I have spatial series of 1200x1200 points. The points were collected over a 24 km x 24 km area at a grid size of 20 m x 20 m. I want to know the dominant frequency or scale of the dataset. I tried to use 'fft2' and the 'fftshift' and plotted using 'imagesc'. The result came as lots of points around a location (600,600) or at the center. I could not understand the output of this. Actually I am looking for the dominant scale or frequency information of this dataset. I am not sure if the FFT2 is the right way to go. I thought, if I can calculate the power spectral density, i might be able to identify the dominant scale. Is there any other way to go? please help me. I appreciate your time and help. thanks a lot in advance. asim

Answer 1

[Rick Rosson]

Please review the following questions:

• http://www.mathworks.com/matlabcentral/answers/13896
• http://www.mathworks.com/matlabcentral/answers/14587