Matlab - reach data from another column based on point selected on graph

Hi!

I have created a program in MATLAB that reads values from a table (*csv) and creates graphs based on that. The table from the file contains 18 columns with values with different types of variables. I used the values from the X column and the Y column to create the graph.

I would like to get the value from another column of the row based on the selected point of the chart.

For example (image below):

When I selected on the indicated point, the values from the table appeared:

X value: -227334

Y value: -39060.2

After manually checking, I can read that the row with these values has a value of "1" assigned in the "Route" column. I would like to automate the search of this table and automatically print the value of the "Route" column for the indicated row.

How could I do that?

Best Regards,

Michael

Answer 1

[Pranjal Kaura]

Hey Michal,

It's my understanding that you want to interact with your plot, get certain values of coordinates (x, y) from the figure by clicking on a particular point and then do further computations based on the values obtained.

You can go through Enable data cursor mode - MATLAB (mathworks.com) documentation to do the same. Here's a code snippet you can refer to:

x = linspace(0, 7, 100);
y = linspace(0, 3, 100);
curve1 = x/6;
curve2 = ones(100, 1)*0.5;
curve3 = ones(100, 1);

f = figure;
plot(x, curve1, 'r', 'LineWidth', 2);
hold on;
plot(x, curve3, 'b', 'LineWidth', 2);
plot(curve2, y, 'k', 'LineWidth', 2);

dcm = datacursormode(f);
dcm.Enable = 'on';
dcm.UpdateFcn = @updateCoordinates;

function txt = updateCoordinates(~,info)
    x = info.Position(1);
    y = info.Position(2);
    disp([x y]); % you can use the coordinates here to index into your table
                 % and find the corresponding row index
    txt = ['(' num2str(x) ', ' num2str(y) ')'];
end

Now that you have the 'x' and 'y' coordinates, you can refer the following code snippet to find the corresponding row in your table having these values.

table = [1 2 3; 4 5 6; 7 8 9];
[row1 col1] = find(table == 7);
[row2 col2] = find(table == 9);
intersect(row1, row2)

Hope this helps!