I have a N*N matrix depicting the intensities at different points in a circular plane. They are different intensities on a disc. How to plot the image?

I have a 10*10 matrix, M depicting the intensities at different points in a disc. The radial vectors of disc is divided as linspace(-1,1 10) and the angle is divided as (0,2*pi,10). Each element in the matrix Mij shows the magnitude for ith radial vector and jth angle. How can we plot the magnitude values in the circular disc space.

[dpb]

@AKHIL, you forgot to attach M

Answer 1

[Matt J]

clc, close all force

N = 10; % Number of polar samples
M = peaks(N); % Example heat map data

T = linspace(0, 2*pi, N)'; % Angular samples
R = linspace(0, 1, N); % Radial samples
[X,Y]=pol2cart(T,R);


figure
pcolor(X, Y, M);
shading interp
colormap(jet)
colorbar
axis equal
title('Polar Heat Map')

[David Goodmanson]

Hi Akhil/Matt

The command in the answer should be

[X,Y] = pol2cart(T,R)

The code provides the answer but depending on your data you can make things look smoother with

N = 10;                         % Number of polar samples
N1 = 180;                       % 2 degree steps 
M = peaks(N);                   % Example heat map data
theta = linspace(0, 2*pi, N);   % Angular samples
r = linspace(0, 1, N);          % Radial samples
theta1 = linspace(0, 2*pi, N1); % Angular samples
r1 = linspace(0, 1, N1);        % Radial samples
[R, T] = meshgrid(r, theta);    % Create polar grid
[R1 T1] = meshgrid(r1,theta1);  % Create polar grid
M1 = interp2(R,T,M,R1,T1);
[X1,Y1] = pol2cart(T1,R1)
figure(2)
pcolor(X1, Y1, M1);
shading interp
colormap(jet)
colorbar
axis equal
title('Polar Heat Map')

[Matt J]

Or perhaps,

N = 10; % Number of polar samples
M = peaks(N); % Example heat map data

Ms=interp2(M,5); %upsampled/smoothed M

T = linspace(0, 2*pi, width(Ms))'; % Angular samples
R = linspace(0, 1, height(Ms)); % Radial samples
[X,Y]=pol2cart(T,R);


figure
pcolor(X,Y,Ms);
shading interp
colormap(jet)
colorbar
axis equal
title('Polar Heat Map')

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