COLORMAP and COLORBAR utilities (Sep 2009)

MATLAB color utilities including COLORMAP join and interpolation; freeze and fit COLORBAR, etc.

Description

These are some utilities that improve the COLORMAP and COLORBAR functions. They are as follows, and each one includes help and examples:
 
COLORMAP utilites:
cmapping - Colormap linear mapping/interpolation.
cmfit - Sets the COLORMAP and CAXIS to specific color bands.
cmjoin - Joins colormaps at certain levels.
cmlines - Change the color of plotted lines using the colormap.
 
COLORBAR utilities:
cbfit - Draws a colorbar with specific color bands between its ticks.
cbfreeze - Freezes the colormap of a colorbar.
cbhandle - Handle of current colorbar axes.
cblabel - Adds a label to the colorbar.
cbunits - Adds units to the colorbar ticklabels.

I include updated versions of the following functions I submitted here previously:
SETCOLORMAPS (now called CMJOIN),
COLORBARFIT (now called CBFIT),
CBLABEL and
CBUNITS.

Enjoy it!
Bugs reports and suggestions will be very appreciated!

Acknowledgements

Usercolormap, Freeze Colors / Unfreeze Colors, Imagescnan.M V2.1 (Aug 2009), Cmapline, and Real2rgb & Colormaps inspired this file.

This file inspired Quiver2.M V1.2 (Nov 2009).

• MATLAB release: MATLAB 7.7 (R2008b)

[Martina Callaghan]

Thanks! Super useful.

[arnold]

cbfreeze deletes my colorbar labels and widens the whole colorbar, and ideas?

[Richard Sims]

Does anyone have a quick and preferably easy solution to stop my colorbar labels dissapearing after cbfreeze is used, the suggestions below are not easy to follow.

[Jakob Sievers]

Incredibly useful!

[Julien Emile-Geay]

It's a clever workaround for one of the most shameful bugs in all of Matlab. Mathworks engineer behold: if your software were written properly, this should never be a problem in the first place. Oh, and every graphic renderer should respect transparency (alpha), that would also be a nice change.

Back to cbfreeze: it works fine but insists on redrawing my horizontal colorbar with a vertical one. Has anyone figured out a fix for that?

[carmen]

Nice work.
the cbfreeze('off') and cbfreeze('del') seem to apply to the whole figure instead of only the current axes. cbfreeze, however, acts on a single axis.

[Rafa]

Useful function thank you.

Just a minor comment: After using cbfreeze on a Horizontal colorbar, the 'XTickLabelMode' property becomes set to 'manual' (differently than the default property which is set to 'auto'. Setting it to manual makes the XTickLabels to be left-aligned and if they have different number of characters (e.g. {'-0.01', '0', '0.01'}) those with less will be not properly aligned with the centre of their XTick positions.

Making sure the 'XTickLabelMode' property keeps as 'auto' in your code should avoid this issue!

Thanks

[Martin Richard]

 

[MrSeniorLoveDaddy]

Good job, thank you.
IAN COLON, try to insert the file cbhandle in your working directory.

[craq]

I had the same problem as Ines and Makarand, but I used a different solution. It might even be possible to include this in cbfreeze.m

I apply cbfreeze before the label, then the width doesn't change. After adding a second axis with a second colorbar, I find the handle to the old colorbar (as the only unknown colorbar handle) and then put the label on.

colorbarHandles=findobj(gcf,'Tag','Colorbar')
for i=1:length(colorbarHandles)
if colorbarHandles(i)~=cBarAxis2
cBarAxis1=colorbarHandles(i);
end
end
ylabel(cBarAxis1,'my label')

[Ian Colon]

It does not work for me. I keep getting an error:
??? Undefined function or method 'cbhandle' for input arguments of type
'double'.

[Leslie]

 

[Andris]

 

[Ines]

Dear Makarand,

I had the same issue, but managed a workaround, which hopefully works for you too.
First I control the colorbar position options so that the it is located slightly farther from the image, and looks much thinner than I want it to be; when I call cbfreeze, the command won't thicken it too much. Regarding the colorbar label, I add it at the very last moment, by deciding its location with [a,b]=ginput, and then writing it with text(a,b,'color_label').

Inès

[Makarand]

There is little bug in cbfreeze. If we have a label to colorbar the lable vanishes after use of cbfreeze and thickness increases.
looking forward for reply

[Matthias Pospiech]

It does not work for me. I have two pcolor plots. If I use cbfreeze the colorbar is displaced with comlete different position values and overlapps with the second pcolor plot. The colorbar is saved, but the first pcolor plot still has the colors of the second pcolor plot. So in result everything looks messed up and the colors of the plots are not saved.

On request I can submit the plot file for testing/debugging.

[David Verrelli]

As I explore this further, I note another problem with the foregoing code:
while the colour scale is logarithmic, as desired, the scale on the z-axis is also logarithmic, which MAY or MAY NOT be desired.

—DIV

[David Verrelli]

Re. my previous post, Solution ID: 1-16X5V does seem to work, and is in fact more elegant than I'd given it credit for.

A more complete example, with a practical application to surface plots (rather than just displaying a raster image) is as follows:
==BEGIN CODE==
[X,Y,D] = peaks;
% D is your 'elevation' data

% Rescale data 1-64
%d = log10(D);
d = real( log10(D) );
mn = min(min(d));
rng = max(max(d))-mn;
d = 1+63*(d-mn)/rng; % Self scale data
%image(d);
surf(d)
hC = colorbar;

LInput = -10:10;
L = 10.^LInput;
% Choose appropriate
% or somehow auto generate colorbar labels
l = 1+63*(log10(L)-mn)/rng; % Tick mark positions
set(hC,'Ytick',l,'YTicklabel',L);
set(gca,'Ztick',l,'ZTicklabel',L);
==END CODE==

This seems to work. The main problem is that the input data goes negative, but that is not a fault of the method per se.

—DIV

[David Verrelli]

I have the same problem as Lachlan Hennessy.
See
http://www.mathworks.com/support/solutions/en/data/1-16X5V/?solution=1-16X5V
and
http://www.mathworks.com/support/solutions/en/data/1-2H5IF9/?solution=1-2H5IF9
They might help.
The latter looks like a slightly more elegant solution, but I can't get it to work, at least with surf. I suspect the only way is the clunky workaround of the first link. Or to dig around inside the colorbar function itself.
—DIV

[Lachlan Hennessy]

cbfreeze does not seem to support log scale colorbars. I have been having some trouble with creating a contourf plot with a logarithmic scale and colorbar. I was hoping that this could be treated in a future update.

Thank you

[Andrea]

Hi everyone, I've got a problem: when I use the function cmapping in the command line it works, but when I try to use it in a GUI there are no errors, but the function does nothing, please help me.

[David]

 

[David]

Hello!

I use cbfreeze in combination with freezeColor and got exactly what I need!!!

THANK YOU!

David

[Carlos Adrian Vargas Aguilera]

There is a little bug on CMAPPING. Magenta 'm' color is colored as red 'r' in v1.0. Well...

Carlos