Explicitly plot figures at the matrix index positions in grid

I want to plot figures(ellipses) corresponding to the value of each element of matrix at their respective positions(Matrix Indices).

For example figure of index A(3,2) should get plotted at Index position 3,2.

[Dyuman Joshi]

Check out - tiledlayout and subplot

If that is not what you want to do, please specify and provide more details/information as to what the expected output is.

[Sakshi]

I want to plot figures(ellipses) at the specified matrix index(rows, columns).

Output should look like the image i have provided.

[Dyuman Joshi]

Did you check out the pages I linked?

[Sakshi]

yes

[Rik]

That isn't effective communication. What did you try? Why didn't it solve your issue? What should be different?

Do you want the ellipses in the same axes? Do you know how to plot one ellipse?

Answer 1

[Garmit Pant]

Hello Sakshi,

I understand that you are trying to plot ellipses in a figure with their position corresponding to their matrix indices.

Your desired plot can be achieved by using the “subplot” function. It will help you accommodate multiple plots in a single figure as a matrix. Please refer the following code snippet demonstrating how to use the function “subplot”.

% Example matrix A with some values 
A = rand(3); % A 3x3 matrix with random values 

% Define the figure 
figure; 

% Get the number of rows and columns 
[rows, cols] = size(A); 

% Loop through each element of the matrix 
for i = 1:rows 
    for j = 1:cols 
        % Create a subplot for each matrix element 
        subplot(rows, cols, (i-1)*cols + j); 
        hold on; % Keep the subplot active to add the ellipse 
        
        % Get the value at the current index 
        value = A(i, j); 
        
        % Define the properties of the ellipse based on the matrix value 
        % Here we use a fixed size for demonstration, but you can scale it by 'value' 
        majorAxisLength = 0.4; % Major axis length 
        minorAxisLength = 0.2; % Minor axis length 
        
        % Calculate the angle for the ellipse points 
        theta = linspace(0, 2*pi, 50); 
        
        % Calculate the x and y coordinates for the ellipse points 
        x = majorAxisLength * cos(theta); 
        y = minorAxisLength * sin(theta); 
        
        % Plot the ellipse centered in the subplot 
        plot(x, y); 
        
        % Set axis limits and aspect ratio 
        axis([-0.5 0.5 -0.5 0.5]); 
        pbaspect([1 1 1]); % Set the aspect ratio to 1:1 
        
        % Remove axis ticks and labels 
        set(gca, 'xtick', []); 
        set(gca, 'ytick', []); 
        set(gca, 'xticklabel', []); 
        set(gca, 'yticklabel', []); 
        
        % Optionally, add a title or text to indicate the matrix value or index 
        title(sprintf('A(%d,%d)=%.2f', i, j, value)); 
        
        hold off; % Release the subplot 
    end 
end 

% Adjust spacing between subplots if necessary 
sgtitle('Ellipses for Each Matrix Element'); % Add a super title (requires R2018b or later) 

For further understanding on the ”subplot” and “pbaspect” functions, you can refer to the following MATLAB Documentation:

1. “subplot”- https://www.mathworks.com/help/matlab/ref/subplot.html
2. “pbaspect” - https://www.mathworks.com/help/matlab/ref/pbaspect.html

I hope you find the above explanation and suggestions useful!