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I am plotting the x,y position of a point over time. I have the data in two vectors, xpos and ypos, and I plot the path of this point using plot(xpos,ypos).

I would like to have this line change color gradually, representing the time axis ( or the index of the x, y vectors).

Is there an easy way to do this?

Rajiv
on 10 Feb 2014

Can be show line plot with different color, if not to use the surface plot as Matt did.

Matt Fig
on 8 Apr 2011

This is one of the classic 'tricks' of MATLAB graphics.

x = 0:.05:2*pi;

y = sin(x);

z = zeros(size(x));

col = x; % This is the color, vary with x in this case.

surface([x;x],[y;y],[z;z],[col;col],...

'facecol','no',...

'edgecol','interp',...

'linew',2);

EDIT

Changed edgecolor to interp and linewidth to 2. This looks less ragged on my machine.

Roy Goodman
on 17 May 2021

I tried this for something I'm working on, and am getting a weird artifact:

Each of the 6 edges of this tetrahedron are computed using the line

surface([x1 x1]',[x2 x2]',[x3 x3]',[y y]',...

'facecolor','none','edgecolor','interp','linewidth',6);

where the arrays x1, x2, x3 parameterize a straight line in 3D space, and y is constant on three of the edges and a monotonically varying sigmoidal function on the other three edges. As you can see from this image, the color index looks very non-monotonic and even noisy on the three edges where the solution varies.

The included graphic was created using the print command, but this is how it appears on the screen as well.

I've tried a few tricks to fix it, neither of which helped

- reducing the number of colors in the colormap
- changing the 'edgecolor' to 'flat'

Daniel Refy
on 7 Mar 2015

N=1 numel(data(:,1)) for a=1:N:numel(data(:,1))-N plot(data(a:a+N,1),data(a:a+N,2),'.','Color',[(a/numel(data(:,1))),0,0] ) hold on end

this will change color of the line from black to red

Paulo Silva
on 8 Apr 2011

Something similar to this:

plot(xpos(1:10),ypos(1:10)) %first points in blue

plot(xpos(11:20),ypos(11:20),'g') %green ones

plot(xpos(21:end),ypos(21:end),'r') %final points in red

another way, the hold all function makes the plots with different color (until the list of available colors ends and after it start from the first one again)

clf

hold all

plot(xpos(1:10),ypos(1:10))

plot(xpos(11:20),ypos(11:20))

plot(xpos(21:31),ypos(21:31))

... %more plots until the end of the indexes

You can insert the code inside a for loop

clf

hold all

N=7; %every N points change color

for a=1:N:numel(xpos)-N

plot(xpos(a:a+N),ypos(a:a+N))

end

Paulo Silva
on 8 Apr 2011

You can change the order of the colors and give the impression of it being continously.

axes

MyColorOrder=get(gca,'ColorOrder'); %RGB combinations per row

%make your own color order, you can even add more row (more possible colors)

set(gca,'ColorOrder',MyColorOrder); %RGB combinations per row

hold all

N=7; %every N points change color

for a=1:N:numel(xpos)-N

plot(xpos(a:a+N),ypos(a:a+N))

end

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