For a known number of plots on the same axis, how do I set the colourscale?

I'm trying to plot my 20 results with a span of rainbow colours and was wondering how you could go about doing this using matlab? Thanks!

Answer 1

[Voss]

data = (1:100).'+(1:20);
n_lines = size(data,2);
colors = jet(n_lines);

figure
colororder(colors);
plot(data)

[Em]

Sorry I should've mentioned that I am using rfplot to plot my graphs so this needs to be done individually for each. Do you have an idea on how to use 'rfplot(s21data)' and the 'hold on' to also achieve this?

[Voss]

Using rfplot works the same. The important thing is to set the axes colororder to the colors you want. In this case, jet generates the colors, and colororder assigns them to be the axes colororder.

hs = sparameters('default.s2p');

n_lines = 8;
colors = jet(n_lines);

figure
colororder(colors);
rfplot(hs,'real')
hold on
rfplot(hs,'abs')

Reference: https://www.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#budumk7_sep_shared-ColorOrder

[Em]

Hi, thank you for this! It's working well. If you don't mind, there is one more thing I'd really appreciate your help with. The colourscale has started repeating itself at some point due to the number of measurements (see image). Do you know how I could stop this from happening?

[Voss]

If the colors are repeating, to prevent that from happening, use (at least) as many colors as you have lines.

• If the number of lines is known in advance of plotting, construct the colormap with that many lines, as shown in my previous comment where I used a jet colormap with 8 colors to color 8 lines.
• If the number of lines is not known in advance or changes as the code runs, you'll have to update the set of colors and apply that to colororder.

However, are you sure the colors are repeating? From the screen shot, I cannot say for sure that's what's happening. It may just be that the line color order is not the same as the line order in the y-direction on the plot. For example, if the first line you plot is of the first color in the colormap and is the bottommost (lowest y) line on the plot, the second line is of the second color and is the second-lowest line, and so on, then yes, it looks like the lines are out of order with what might be a typical colormap. But I don't know that the lines are in that order in terms of the y on the plot, and I don't know what the colormap is.

If you are already using (at least) as many colors as lines, or changing that doesn't fix the problem, please share some code I can run to take a look.