highlighting a datapoint in a plot of data specific to a state using a checkbox

Hi all,

I am very new to matlab, and am trying to add a component to an app I'm making. The app plots an x,y set of data from an excel spread sheet. each point is specific to a N.A. state. I want to add a check box for each state that when checked, will circle the data point asssociated to that state without getting rid of the rest of the points on my plot. I could also use a dropdown if its easier.

Thanks for your time,

Liam

Answer 1

[Suraj Kumar]

Hi Liam,

To highlight a point on a plot that is selected from a dropdown menu , you can refer to the following code snippet.

To add a dropdown menu for the data extracted from an excel file:

function LoadButtonPushed(app, event) 

            [file, path] = uigetfile('data.xlsx', 'Select an Excel file'); 
            if isequal(file, 0) 
               return; 
            end  
            fullPath = fullfile(path, file); 
            data = readmatrix(fullPath); 
            app.xData = data(:, 1); 
            app.yData = data(:, 2);  
            % Plot the data 
            plot(app.UIAxes, app.xData, app.yData, 'b-'); 
            numPoints = length(app.xData);  
            dropdownItems = arrayfun(@(i) sprintf('Point %d', i), 1:numPoints, 'UniformOutput', false);  
            app.DropDown.Items = dropdownItems; 

end 

This code opens a file selection dialog, reads data from the selected Excel file, plots the data, updates the dropdown menu with point identifiers.

Now, after populating the dropdown menu with data points, highlight the point whenever it is selected from the menu by adding a specific marker on the data point in the plot.

 function PointSelectionDropDownValueChanged(app, event)  
         pointIndex = str2double(regexp(event.Value, '\d+', 'match', 'once'));   
            if ~isempty(app.HighlightedPoint) && isvalid(app.HighlightedPoint)  
                delete(app.HighlightedPoint);  
            end  
            % Highlight the selected point  
            hold(app.UIAxes, 'on');    
            app.HighlightedPoint = plot(app.UIAxes, app.xData(pointIndex), app.yData(pointIndex), 'ro', 'MarkerSize', 10);   
            hold(app.UIAxes, 'off');  
        end 

You might find these resources helpful:

1. https://www.mathworks.com/help/matlab/ref/plot.html

2. https://www.mathworks.com/help/matlab/creating_guis/mortgage-app-or-gui-in-app-designer.html

Hope this helps!