Interactive data tip specify x and y location

Hello,

I would like to plot a heatmap or an image and use data tip where I can manually enter the x and y location in a sperate window and get the data tip displayed and/or the z-coordinate displayed in the image or in a new window.

So I would interactively enter different x and y location and always get the correspoding z value.

How can I do this?

Thanks.

[Mathieu NOE]

hello

would suggest you look at this excellent FEX submission

plenty of demo examples

plt - File Exchange - MATLAB Central (mathworks.com)

Answer 1

[Narvik]

Hi Konvictus177,

As per my understanding, you would like to create an interactive plot where you can enter x and y coordinates to display the corresponding z-value from a matrix.

You can do this via MATLAB GUI. Refer to the following documentation link for more information on MATLAB GUI:

https://www.mathworks.com/discovery/matlab-gui.html

The following example code demonstrates how to achieve interactive plot with input coordinates using a simple GUI with a heatmap and a text input for coordinates.

function interactiveHeatmap()
    % create example data 10x10 data
    data = peaks(10);
    [xSize, ySize] = size(data);

    % create figure and heatmap
    hFig = figure('Name', 'Interactive Heatmap', 'NumberTitle', 'off');
    hMap = heatmap(data);
    title('Interactive Heatmap');
    xlabel('X');
    ylabel('Y');

    % create uicontrols for input
    uicontrol('Style', 'text', 'Position', [20 20 100 20], 'String', 'Enter X:');
    xInput = uicontrol('Style', 'edit', 'Position', [130 20 50 20]);

    uicontrol('Style', 'text', 'Position', [200 20 100 20], 'String', 'Enter Y:');
    yInput = uicontrol('Style', 'edit', 'Position', [310 20 50 20]);

    % button to update data tip
    uicontrol('Style', 'pushbutton', 'Position', [380 20 100 20], ...
              'String', 'Show Z', 'Callback', @updateDataTip);

    % create a textbox for displaying the z-value
    zText = annotation('textbox', [0.15, 0.85, 0.1, 0.1], 'String', '', ...
                       'FitBoxToText', 'on', 'BackgroundColor', 'white');
    
    % function to update the z value
    function updateDataTip(~, ~)
        % get input values
        x = str2double(get(xInput, 'String'));
        y = str2double(get(yInput, 'String'));

        % validate input
        if isnan(x) || isnan(y) || x < 1 || y < 1 || x > xSize || y > ySize
            errordlg('Invalid coordinates', 'Error');
            return;
        end

        % get the z-value
        z = data(y, x);

        % update the text annotation to display the z-value
        set(zText, 'String', sprintf('Z: %.3f', z));
    end
end

I hope this helps!