how can I get index from ginput?

Hello,

I need a help on how to get index from ginput on a plot:

I have x axis = time(timef), yaxis = force(datan):

I've tried this code bellow but it doesn't work:

figure, plot( timef, datan, 'LineWidth',1.5, 'Color', '[0.301,0.745,0.933]' );

title('Calibrated Force')

xlabel('Time (s)')

% start/end time range

for i = 1:1

[strt(i),~] = ginput(1);

[fin(i),~] = ginput(1);

calcStart = find(timef == round(strt(i)));

calcEnd = find(timef == round(fin(i)));

Thanks!

Answer 1

[Image Analyst]

ginput(1) asks the user to click on one point and it returns the x and y value of that point. There is no index since it's just one points. Then you take the x value and stick in into strt(i). Then you repeat that and put the next x value where the user clicks and put it into fin(i).

What I think you really want to do is to find out what index of your array is closest to the x value of where they clicked. Untested code:

for k = 1:1
    uiwait(helpdlg('Please click on the starting and ending points.'));
    [x, y] = ginput(2);
    distances1 = abs(timef - x(1));
    [minDistance, indexOfMin1] = min(distances1);
    distances2 = abs(timef - x(2));
    [minDistance, indexOfMin2] = min(distances2);
    indexStart(k) = indexOfMin1;       % Save index of starting time.
    indexEnd(k)   = indexOfMin2;       % Save index of ending time.
    timeStart(k) = timef(indexOfMin1); % Save starting time.
    timeEnd(k)   = timef(indexOfMin2); % Save ending time.
end

[Binu]

Hi, I found this today and it helped to solve my issue. Thank a lot.