Shade an area in a plot between two Y values
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Christoph Meier
on 15 Sep 2015
Commented: Star Strider
on 19 Mar 2023
Dear MATLAB community,
I have a time series plot, and would like to shade specific regions in light grey (transparent).
The time series plot is an economic process, and I would like to shade times of recessions.
That is, I already have the values of the y-axis (the respective start date and end date of a recession), and I already have a nice plot, but I cannot figure out how to add these 'recession shadings'.
In short: I would like to shade an area in a time series plot, and the area is defined as:
X(:) % all x
Y(y1,y2) % between y1 and y2
Thank you!
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Accepted Answer
Star Strider
on 16 Sep 2015
Edited: Star Strider
on 16 Sep 2015
See if this does what you want:
x = linspace(0, 10, 10);
y = randi(9, 1, 10);
ybars = [2 6];
figure(1)
hp = plot(x, y, 'bp');
hold on
patch([min(xlim) max(xlim) max(xlim) min(xlim)], [ybars(1) ybars(1), ybars(2) ybars(2)], [0.8 0.8 0.8])
plot(x, y, 'bp')
hold off
axis([0 10 0 10])
You will have to modifiy it to do what you want, but that should be straightforward. Note the repeated plot call to prevent the patch from hiding it.
More Answers (2)
Narendra Sharma MadanLal Sharma
on 14 Aug 2017
Thanks a lot ,Star Strider!
2 Comments
Jonathan Bishop
on 24 May 2019
Didn't spend more than a minute on this so possibly there is more to it, but if using a legend, both the patch and the double call to plot will affect the current spot in the ordered list of plot colors. Set the patch handlevisibility to 'off' and use cla after the first plot, if you don't want to bother dealing with the color order in a more programmatic fashion.
A K M Kamrul Hasan
on 22 Jan 2020
Hi,
This discussion is about the srea bounded by straight lines. However, is it possible to shade an area in Matlab plot bounded by straight lines and curved lines? (i.e like the attached image) ?
Regards,
Kamrul Hasan ![1486289316.png](https://www.mathworks.com/matlabcentral/answers/uploaded_files/264847/1486289316.png)
![1486289316.png](https://www.mathworks.com/matlabcentral/answers/uploaded_files/264847/1486289316.png)
3 Comments
Star Strider
on 19 Mar 2023
Just seeing this now.
Yes! It is definitely possible.
x = linspace(0, pi);
y = sin(x);
Pm = 0.5;
xPm = interp1(y(x<=pi/2), x(x<=pi/2), Pm) % Calculate Interseection
deltam = interp1(y(x>=pi/2), x(x>=pi/2), Pm) % Calculate Interseection
figure
plot(x, y)
Lv1 = (x>=pi/2) & (y>=Pm); % Logical Vector
Lv2 = (x>=xPm) & (x<=pi/2); % Logical Vector
patch([x(Lv1) flip(x(Lv1))], [ones(size(x(Lv1)))*Pm flip(y(Lv1))], 'r' ) % Call 'patch'
patch([x(Lv2) flip(x(Lv2))], [zeros(size(x(Lv2))) ones(size(y(Lv2)))*Pm], 'r') % Call 'patch'
yline(Pm,'-k','P_m', 'LabelHorizontalAlignment','left', 'FontWeight','bold')
text(median(x(Lv2)), Pm/2, 'A_1', 'Horiz','center', 'Vert','top')
text(median(x(Lv1)), (max(y)+Pm)/2, 'A_2', 'Horiz','right', 'Vert','top')
hold on
plot([1 1]*deltam, [0 Pm], '--k')
hold off
It’s worth noting how ‘Lv’ is constructed. It combines the logical values where
and
to create the appropriate bounding region to fill with patch.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1329840/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1329845/image.png)
Add the other text calls to create text in the appropriate places. The x-axis location for
has been calculated.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1329850/image.png)
.
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