How do I make a color bar of a loglog plot represent various exponents of plotted curves?

I have a loglog plot on which I have plotted various curves with different exponential values (noted in the legend). My goal is to not have the legend, but instead, have a colour bar that associates the colour of the curve with values of the powers of ten. I.e., I have curves plotted for each value of 10^x, where x = [-3, ..., 3] by integer, and I would like to have, say, red be the the colour of the line associated with 10^3 and blue be associated with the line 10^-3, with a gradient in between.

Answer 1

[Benjamin Kraus]

I'm not 100% sure I understood your question. If I understood correctly, you still want 7 lines, with 7 different colors (so the plot itself won't change), but instead of a legend you want a colorbar.

The first thing I think you will need to change to get that working is the colors. The default 7 colors come from the axes ColorOrder, and are not part of a colormap. In fact, they are 7 colors picked to be distinct from one another, instead of part of a gradient.

To pick 7 colors from a gradient, you can use something like the parula colormap:

colors = parula(7);

Now you can plot your 7 lines, and specify your 7 colors. Note: It is up to you to make sure lines are colored in the correct order based on the data and ticks you select later.

madeupdata = magic(7);
p = loglog(madeupdata);
for ii = 1:7
    p(ii).Color = colors(ii,:);
end
% set(p,{'Color'},mat2cell(colors,ones(1,7))) % Same as for loop above.

Once that is done, you need to create a colorbar with the same colormap, and manually set the ticks:

set(gca,'CLim',[-3 3]);
c = colorbar;
c.Colormap = parula;
c.Limits = [-3 3];
c.Ticks = -3:3;

Does that get you close to what you are trying to do?

[Ian Hoppock]

Success! Thank you.

[SHANMUKHA REDDY AMARAVADI]

how did you do that? #Ian Hoppock