This might be what you're looking for. ginput() allows you to click on a graph as many times as you'd like and it returns a 2-column matrix of x,y coordnates where you clicked.
Demo 1
Run this, click around the axes, press Enter to see where you clicked. xy will be the coordinate of your clicks.
figure
xy = ginput(); % now click as many coordinates as you'd like then press Enter when finished.
plot(xy(:,1), xy(:,2), 'bo', 'MarkerSize', 8, 'MarkerFaceColor', 'b');
Demo 2
This version plots as you click instead of plotting at the end. Press Enter to stop. xy will be the coordinate of your most recent click.
figure
axh = axes;
hold(axh, 'on')
xy = [0,0];
while ~isempty(xy)
xy = ginput(1);
if ~isempty(xy)
plot(axh, xy(1), xy(2), 'bo', 'MarkerSize', 8, 'MarkerFaceColor', 'b');
end
end
