Vertical lines with text in plot

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.

1 个评论

From the bottom of the figure to the top, or from the axes?

请先登录,再进行评论。

 采纳的回答

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 个评论

Sepp
Sepp 2017-9-28
编辑:Sepp 2017-9-28
Thanks for your answer. For the text you have used 0.7*[1 1 1] where 1 is the upper bound of the figure. Unfortunately, the upper bound in my figure is flexible and ylim instead of 1 does not work (I'm getting an error). Is there a possibility to make it flexible?
yl = ylim() ;
text([1 3 5], yl(2)*0.7*[1 1 1], {'Test 1', 'Test 2', 'Test 3'})
@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.

请先登录,再进行评论。

更多回答(1 个)

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.

类别

帮助中心File Exchange 中查找有关 Line Plots 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by