# Vertical lines with text in plot

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Sepp on 27 Sep 2017
Commented: Yair Altman on 17 Oct 2017
Hello everybody
I have created a plot in Matlab. Let's assume for simplicity that I have the following plot:
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)
Now I would like to add vertical lines (going from the bottom of the figure to the top) at positions x = 1, x = 3 and x = 5. Additionally, the vertical lines should have text (next to the line or on top of the line). For example, for the line at x = 1 I would like to have the text "test 1".
How can this be done? This seems to be a pretty tricky thing in Matlab.
Jan on 27 Sep 2017
From the bottom of the figure to the top, or from the axes?

Star Strider on 27 Sep 2017
To draw the lines, you need to specify duplicate x-coordinates to match the two-element ylim vectors. Here, the ylim matrix is transposed (the ' operator) so the vertical lines plot correctly.
The text call to label the lines is straightforward. You need to provide a vector of x and y coordinates, and a matching cell array of strings.
Try this:
x = 0:pi/100:2*pi;
y = sin(x);
figure(1)
plot(x,y)
hold on
plot([1 3 5; 1 3 5], [ylim; ylim; ylim]')
hold off
text([1 3 5], 0.7*[1 1 1], {'Test 1', 'Test 2', 'Test 3'})
It’s not ‘tricky’ really. It just requires a bit of experience with the functions, and when necessary, experimentation to see what works.
##### 3 CommentsShow 1 older commentHide 1 older comment
Cedric Wannaz on 28 Sep 2017
yl = ylim() ;
text([1 3 5], yl(2)*0.7*[1 1 1], {'Test 1', 'Test 2', 'Test 3'})
Star Strider on 28 Sep 2017
@Cedric — Thank you! (I was off doing other things for a few minutes.)
@Sepp — My pleasure. The key is to use ylim to scale the y-position of the labels. The advantage is that with ylim (in Cedric’s comment, yl(2) is the upper limit of the y-axis) automatically rescales with changing limits of the y-axis.

Jan on 27 Sep 2017
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y);
hold('on');
line([1 3 5; 1 3 5], [-10, -10, -10; 10, 10, 10], 'YLimInclude', 'off');
text([1 3 5], [1, 1, 1], {'Test 1', 'Test 2', 'Test 3'}, ...
'VerticalAlignment', 'top')
Disabling 'YLimInclude' let the Y-limits untouched by this object. Then you can even Zoom in the diagram without seeing the end of the line (at least until a certain level). Unfortunately YLimInclude is undocumented, but it works for many years now.
Yair Altman on 17 Oct 2017
Here is the unofficial documentation for the undocumented YLimInclude property: http://undocumentedmatlab.com/blog/plot-liminclude-properties