Polar coordinate plot with color

Hi all,

I am trying to create points on the polar grid and color code each point. The MATLAB polar function allows one color per call, so I am looping roughly 15,000 times to generate the figure I need.

The section of code below takes 20 minutes to execute. Are there ways to make this code more time efficient given the limitation of the polar function?

David

%-------------------------
% polar plots
map=colormap; close

theta = phase1(mask).*pi/180;
rho   = amplitude1(mask);
gof   = gof1(mask);
ccode = round(gof*63+1);
%-------------------------
for i=1:length(theta) %15,000
   if i==1
       figure
       h = polar(theta(i),rho(i),'o');
       set(h, 'MarkerFaceColor', map(ccode(i),:));
   else
       h = polar(theta(i),rho(i),'o');
       set(h, 'MarkerFaceColor', map(ccode(i),:));
   end
end
%-------------------------

Answer 1

[Walter Roberson]

Is your code perhaps missing a "hold on" ?

Could you polar() once to get the background, hold on, then scatter() of pol2cart() of everything at once to draw the points?

The first point you should polar() should be the one with the largest rho so that you get the rings drawn correctly.

By the way, with the code you have, why not call figure once first before the loop, and then your loop would not need any "if" statement?

[Dave]

While I was prepping my code for posting, I deleted a "hold on" by mistake. Thank you very much for your valuable comment. Your suggestion did the trick!

Here is a much more concise and time efficient code that generates the figure I need instantly.

theta = phase1(mask).*pi/180;

rho = cbf1(mask);

gof = gof1(mask);

[X,Y] = pol2cart(theta,rho); S = 15;

figure

h_fake = polar(theta_,1500*ones(size(theta_))); % set radius to 1500

hold on

set(h_fake, 'Visible', 'Off');

scatter(X, Y, S, gof,'filled');

colorbar

Cheers,

David