Colored line or scatter plot

Plot lines with CData, (actually surface)

Description

plots a 2-D "line" with c-data as color
Makes a surface object and the colouring is controlled by the colormap.

Examples:
x = 0:0.1:2*pi;
color_line(x,sin(x),sin(x))
color_line(x,cos(x),cos(x),'*')

• Acknowledgements: This submission has inspired the following:; 3D colored line plot
• MATLAB release: MATLAB 7.6 (R2008a)

[d luc]

thanks--this is a useful routine for plotting 2-d vectors (e.g. U=[u,v]) on a [u,v] plane, where the color gives the sense of rotation (time evolution) of the vector.

[Ed Mackay]

Useful function which avoids creating separate line segments for each color. The coloured line produced is a single MATLAB graphics object.

[Carlos Adrian Vargas Aguilera]

This is nice Pekka, I recommend you to include a screenshot.

My 'low' rating is because if the length of the series is short (10 elements for example) the colors are different for the same y-values. My suggestion is to generate colorbands in the y-axis and make linear interpolations in these bands.

Regards, Carlos

[Tristan Desrues]

Perfect !!
let you plot large dataset of coordinate, colored with velocity, in 1 line:
color_line(x,y,sqrt(vx.^2+vy.^2),'.')

instead of
for i=1:numel(x)
    plot(x(i),y(i),'.','color',myColorMap(sqrt(vx(i)^2+vy(i)^2)))
end

And it's a lot faster!!
thx!!

[Georg Stillfried]

Nice. Just what I needed!

[David]

Doesn't seem to work with R2008b. The following is returned for the example:

Warning: size(CData) must equal size(ZData) or size(ZData)-1 for flat shading

[Shinya Ito]

Exactly what I was looking for! Thanks!

[Ulrich]

Unfortunately in my hands this function only seems to work for x shorter than 300 elements.

For example:

x = 1:301
color_line(x,sin(x),cos(x))

never generates a plot(i.e. the plot window never refreshes.)

For x=1:300 it works beautifully though.
Is there a simply way to make it work for longer x (e.g. 2500 points).

[Pekka Kumpulainen]

^ works fine up to million elements (didn't try with more).
The function does NOT refresh the plot. It only adds a new colored line.
Maybe you should clear the figure (clf).