Plot deviation of curve as shaded area inside
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Sokratis Panagiotidis
on 22 Jul 2022
Commented: Sokratis Panagiotidis
on 23 Jul 2022
Hi,
A common question here in this forum is how to plot an area between two curves.
Here's one type of a common answer:
x = transpose(1:100);
y = x.^2;
curve1 = y*1.05;
curve2 = y*0.95;
x2 = [x flipud(x)];
inBetween = [curve1, curve2];
fill(x2, inBetween, 'k', 'LineStyle', 'none');
hold on;
plot(x, y, 'r', 'LineWidth', 2);
This is the result I get:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1074435/image.png)
I used
alpha(.1)
to make the shaded area transparent.
What I would like to have is the area between those two curves shaded, since I want to show the red curve's deviation without having to use the green lines. Hence why I removed the Linestyle. But I get something like a linear fill between the starting and endpoint of the vectors.
How can I do that without too many lines of code? I'm afraid my laptop is at a certain limit with the actual length of vectors I have to plot (>800.000 values).
Also if you know if and how it's possible to alternate the shaded area like a zebra (white-black-white-black, etc) I'd appreciate if you tell me that!
Thank you!
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Accepted Answer
Star Strider
on 22 Jul 2022
x = transpose(1:100);
y = x.^2;
curve1 = y*1.05;
curve2 = y*0.95;
x2 = [x flipud(x)];
inBetween = [curve1 curve2];
patch([x; flip(x)], [inBetween(:,1); flip(inBetween(:,2))], 'k', 'LineStyle', 'none', 'FaceAlpha',0.25);
hold on;
plot(x, y, 'r', 'LineWidth', 2);
The approach to writing patch calls is to provide a defined area that the function can fill. Here, that is provided by plotting ‘curve1’ against ‘x’ and then plotting ‘flip(curve2)’ against ‘flip(x)’ completing the region to be filled.
.
2 Comments
More Answers (1)
Bjorn Gustavsson
on 22 Jul 2022
Edited: Bjorn Gustavsson
on 22 Jul 2022
Have a look at the file exchange. There there are multiple "shaded-error-plots". For example (without ordering of merit):
I have used a majority of these functions at different times to god result, now I have no memory of why one or the other was preferable.
HTH
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