Plot contour for polar coordinate

Hello; How to plot contours for polar coordinate. I have The pressure distribution for angle theta and R. Thank you.

Answer 1

[Jacob Mathew]

Hi Djamel,

You can use meshgrid and contourf functions in tandem to plot a contour with polar coordinates. The following example demonstrates it:

% Define Z axis
Z = @(r, theta) cos(r) .* sin(theta);

% Define the grid in polar coordinates
r = linspace(0, 3, 100);          % Radius
theta = linspace(0, 2*pi, 100);   % Angle

% Create a meshgrid
[R, Theta] = meshgrid(r, theta);

% Compute Z values
Z_values = Z(R, Theta);

% Convert polar to Cartesian coordinates
X = R .* cos(Theta);
Y = R .* sin(Theta);

% Create the contour plot
figure;
contourf(X, Y, Z_values, 'LineStyle', 'none');
colorbar;
title('Contour Plot in Polar Coordinates');
xlabel('X');
ylabel('Y');
axis equal;

You can refer to the documentation for meshgrid and contourf functions below:

https://www.mathworks.com/help/releases/R2024a/matlab/ref/meshgrid.html

https://www.mathworks.com/help/releases/R2024a/matlab/ref/contourf.html