Directional wave spectrum plot (polar plot)

Dear all,
I am trying to calculate directional wave spectrum using matlab programs developed by Dr. Lee Gordon and provided by Nortek.

Now I would like to plot directional wave spectrum using polar plot (see attached figure for an example).
An output parameter of wds.m or llfft.m, F, is frequency discretization; however, I cannot find that of wave directional discretization.

Here is what I am doing so far.
Directional wave spectra are calculated as the product of frequency spectra and directional spreading, both of which can be obtained through the matlab programs.

S(F,theta)= Sp(F) * Spread (theta)

Once the parameters of direction and frequency discretization are obtained, make matrix and direction and frequency are converted using
[dir,f]=meshgrid(DIR*pi/180,F);
[x,y]=pol2cart(dir*pi/180,f);
(Now I am stuck here)  

Then, draw polar plot using pcolor or contour command.
pcolor(x,y,S); or contour(x,y,S);

Could anyone help me how to decide the directional discretization for polar plot?

Sincerely,


Daijiro Kobashi
Louisiana State University

Hello Daijiro,

When I display the "full wave directional distribution", I generally use a discretization of 4 degrees.

I am more concerned about how you are using the output from Lee Gordons MatLab programs.  The scripts appear to provide wave parameters of height, period, direction, and spread.  However nothing containing the full wave directional distribution over frequency and direction, nor any of the Fourier coefficients that are commonly used to present the full directional distribution.

Again I am sorry that I can not be of more help with these MatLab scripts.  

kind regards,
Torstein