How to make a heat map using three variables?

Hey,

I have an equation calculating the concentration depending on 2 variables (r and theta). I want to make a plot of r vs. theta that shows the concentration at certain points (e.g. for the axis x => r, y=> theta, z => concentration).

I used the following code to calculate the values and generate a matrix A containing the concentration at different r and theta values.

c_1 = 0.5;      
R = 10^(-3);    
N = 100; 
theta = linspace(0,pi/2,N); 
r = linspace(0,R,N);        

for i = 1:1:N
    for j = 1:1:N
    A(i,j) = c_1 .* (r(i)./R) .* cos(theta(j));
    end
end

The matrix A has (of course) the dimensions N x N. But I don't really know how to make a nice plot for this. Can anyone help me?

Kind regards,

Danny

Answer 1

[KSSV]

c_1 = 0.5;      
R = 10^(-3);    
N = 100; 
theta = linspace(0,pi/2,N); 
r = linspace(0,R,N);        
[r,theta] = meshgrid(r,theta) ; 
A = c_1*(r/R).*cos(theta);
pcolor(r,theta,A)
shading interp 
colorbar

[Danny Helwegen]

Thanks, that was what i was looking for. Is there some kind of "thermometer" possible on the side that links color to a concentration value?

[KSSV]

Use colorbar.

[Danny Helwegen]

Thanks for your help, it works