# Filled 2D plot

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Ironhide Jr on 16 Apr 2021 at 2:07
Commented: Star Strider on 18 Apr 2021 at 1:36
I have 3 vectors, X,Y,Z in which X,Y generates one plot and X,Z generates another. However, what I want to do is plot X,Y as a 2D plot and fill the area between the curve and the X axis with colors based on the Z values. I tried using the contour plot but failed. However, then I managed to change the colour of the curve based on the Z value as follows, but I need the complete area under the curve to be filled. Is there any advice?
c= cos(Z).^2;
colormap(hsv)
patch(X,Y,Z,c,'FaceColor','none','EdgeColor','interp')
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Ironhide Jr on 16 Apr 2021 at 11:03
A brief example of the data would be as,
X=1:22000;
Y=2:2:44000;
Z=rand(1,22000);
Now I can plot X and Y in 2D as well as X and Z in 2D. However, to make the data more concise, I am trying to plot a single figure of X vs Y in which, the area under the curve is colored based on the value of Z at that region.
I have also attached an actual dataset marked directly as X,Y and Z.
Thank you

Star Strider on 17 Apr 2021 at 1:53
My apologies for the delay. I was working on other things most of today.
However, to make the data more concise, I am trying to plot a single figure of X vs Y in which, the area under the curve is colored based on the value of Z at that region.
This was a bit of a challenge! However it seems to do what was requested.
The Code —
X = XL.X;
Y = YL.Y;
Z = ZL.Z;
figure
plot(X, Y)
hold on
patch([X; flipud(X)], [Y; zeros(size(Y))], [Z; flipud(Z)])
hold off
grid
cb = colorbar;
cb.Label.String = 'Z Value';
xlabel('X')
ylabel('Y')
title('Full Patch Plot')
figure
plot(X, Y)
hold on
patch([X; flipud(X)], [Y; zeros(size(Y))], [Z; flipud(Z)])
hold off
grid
cb = colorbar;
cb.Label.String = 'Z Value';
xlabel('X')
ylabel('Y')
title('Zoom Detail Patch Plot')
axis([0 20 0 5E-3])
figure
plot(X, Z)
grid
The Plots —
The ‘Z’ value is very high only in a very small part of the patch object, so the ‘zoomed’ plot is necessary to demonstrate that the code does what was requested. The maximum value of ‘Z’ occurs at an ‘X’ value of about 3.22, and that is where the colour changes the most. The ‘Z’ value is actually quite noisy, accounting for the ‘striated’ appearance of the patch colours.
Star Strider on 18 Apr 2021 at 1:36
As always, my pleasure!

R2019b

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