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

The author wishes to acknowledge the following in the creation of this submission:
usercolormap, freezeColors / unfreezeColors, imagescnan.m v2.1 (Aug 2009), CMAPLINE, real2rgb & colormaps
This submission has inspired the following:
quiver2.m v1.2 (Nov 2009)

• MATLAB release: MATLAB 7.7 (R2008b)

[Carlos Adrian Vargas Aguilera]

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

Carlos

[David]

Hello!

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

THANK YOU!

David

[David]

 

[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.

[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

[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

[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]

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

[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.

[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

[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

[Andris]

 

[Leslie]

 

[Ian Colon]

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

[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')

[MrSeniorLoveDaddy]

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