MATLAB: Vertical lines with text in plot

figureplotvertical line

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.

Best Answer

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.
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