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Fill area between two curves

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Hello,
I am tring to fill the area between the two ellipses. I am importing the values from Excel to plot the figure. After that I would like to fill the two ellipses with two different colors. How do I do that?.
CODE:
clc
clear all
load Phase12.mat
x = Phase1.x;
y = Phase1.z;
plot(x,y);
fill(x,y,'g');
hold on
a = Phase1.a;
b = Phase1.b;
plot(a,b);
% fill(a,b,'q')
x,y,a and b are the names of the four columns that I have imported from excel. x,y represents the bigger ellipse. I tried using some of the patch codes, but it did not work out. Can someone please help me with this?
  1 Comment
Adam Danz
Adam Danz on 2 Apr 2021
Just FYI so you don't have to wait for your answers in the future, this topic has been addressed many times in the forum and there is a clear example in the patch documentation.

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Accepted Answer

Star Strider
Star Strider on 16 Feb 2021
Try something like this:
t = linspace(0, 2*pi);
x = ([1;2]*cos(t)).'; % Produces (Nx2) Matrix
y = ([1;2]*sin(t)).'; % Produces (Nx2) Matrix
figure
patch([x(:,2); flipud(x(:,1))], [y(:,2); flipud(y(:,1))], 'g', 'EdgeColor','none') % Create ‘patch’ Object
hold on
plot(x(:,1), y(:,1), '-r') % Circle Outlines
plot(x(:,2), y(:,2), '-r') % Circle Outlines
hold off
axis('equal')
If your data are row vectors, do this:
patch([x fliplr(a)], [y fliplr(b)], 'g')
If they are column vectors:
patch([x; flipud(a)], [y; flipud(b)], 'g')
That should work.
  36 Comments
Star Strider
Star Strider on 14 May 2021
As always, my pleasure!
Apparently the data file changed (I have been away doing other things), since it is not the same one I initially plotted.

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