Make a polar plot from data

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kayak
kayak on 11 Feb 2013
I am trying to make a polar plot of a set of data in file called 't8m'. I am calculating parameters as:
  1. theta angle = arccos (column 4)
  2. bin width = 10 (making a total of 18 bins between 0 and 180deg).
  3. length of each bin should be = (number of the theta angles that fall in the bin)/total number of all angles between 0 and \pi. This can be seen as length of array within the bin/length of array in that frame.
I am having problems with the for loop and the polar plot command. Can someone help out with this loop? Here is what I have now:
izm=length(t8m)
theta = acosd(nz) ;
for i = drange(0:10:180)
k= 0.0
for j = 1:izm
if theta == i
k = k+1
lth1 = k/length(k)
end
end
end
polar(theta,lth1,'--r')

Accepted Answer

Thorsten
Thorsten on 12 Feb 2013
theta = pi*rand(1, 100);
th = linspace(pi/10, pi, 10);
hi = hist(theta, th);
polar(th, hi/numel(theta))
  2 Comments
kayak
kayak on 13 Feb 2013
Thanks Thorsten, but now I don't get it. It seems you replaced the theta calculation (theta = acos (nz)) completely. I still want the angle to be calculated as arccos, but the scaling should be between 0 and 1.
Thorsten
Thorsten on 13 Feb 2013
Edited: Thorsten on 13 Feb 2013
Sorry for the confusion. I just generated some sample data (because I do not have nz), using
theta = pi*rand(1, 100);
Of course you have to use
theta = acos(nz);

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More Answers (1)

Thorsten
Thorsten on 11 Feb 2013
Edited: Thorsten on 11 Feb 2013
theta = acos(nz);
rose(theta)
  3 Comments
Thorsten
Thorsten on 11 Feb 2013
Edited: Thorsten on 11 Feb 2013
Hi Kayak, rose is an angular histogram that does the sorting for you, if theta is a bunch of angles in radiant.
kayak
kayak on 12 Feb 2013
Thanks, I get it now. After using the command:
rose(theta, 18),
I want to scale this with the length of the whole array (ie length (theta))so that the bar length lies between 0 and 1. Do you know how I can do this? I have tried plotting:
rose ((theta/length(theta)), 18)
but this is showing only one bar. Can someone help please.

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