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colorGray

version 1.0.0.0 (1.6 KB) by Alexandre Tumlinson

Alexandre Tumlinson (view profile)
Creates full spectrum, blue-green-orange-salmon, colormap that maps to linear grayscale.
4.4
9 Ratings

1 Download

Updated 17 Nov 2006

No License

Creates a broad range color map that looks good in color as well as when reduced to grayscale for low cost publication.

Finished colormap encodes small values with a bluish color, intermediate values in green to orange, and large values with a redish/salmon color. The greyscale is linear.

RGBcolormap=colorGray(numberOfLevels,makeDebugPlot);

Cite As

Alexandre Tumlinson (2020). colorGray (https://www.mathworks.com/matlabcentral/fileexchange/12804-colorgray), MATLAB Central File Exchange. Retrieved .

Comments and Ratings (12)

Davide

Davide (view profile)

Pretty nice colormap but as already noted by Will Robertson it crashes for number of leves < 3.
This can be a rough solution.
Add this after the nargin checks:

if numLevels==1
numLevels= size(colormap, 1);
realnumLevels=1;
elseif numLevels==2
numLevels= size(colormap, 1);
realnumLevels=2;
else
realnumLevels=numLevels;
end

And this before the debug plot option:
if realnumLevels==1
RGBmap = RGBmap(1,:);
elseif realnumLevels==2
RGBmap = [RGBmap(1,:); RGBmap(end,:)];
end

Raj

Raj (view profile)

It looks like Mathworks has basically taken this idea and made it the new default colormap: http://blogs.mathworks.com/steve/2014/10/13/a-new-colormap-for-matlab-part-1-introduction/

Matteo Niccoli

Matteo Niccoli (view profile)

Great colormap

Raj

Raj (view profile)

I love this colormap. I've used it exclusively in all my MATLAB work since I discovered it. Great submission.

Ondrej

Ondrej (view profile)

Other suggestion is to add line:

colormap(rgb2gray(RGBmap));colorbar

in the debugplot option to see the resulting grayscale.

Ondrej

Ondrej (view profile)

What about adding a next optional parameter which would set the "darkness/lightness", such that the mapping between color and grayscale wouldn't be linear.
Easy way how to do is to add a line, e.g.
RGBmap = brighten(RGBmap,0.2)
The problem is, however, that the mapping is not smooth (as can be seen on the plot, if I do e.g. colorGray(100,1)).

Ondrej

Ondrej (view profile)

Oliver Woodford

Oliver Woodford (view profile)

I wrote something like this (independently) myself. However, it is full greyscale (i.e. black to white) and has a wider gamut of colours. It is available as the 'contrast' colourmap of the SC package (id 16233), which also has other "colour to gray" colourmaps too: 'earth', 'pinker', 'pastel'.

Manuel Guizar

The code works well but it does not use the entire gray scale range.

Garret B

Alex is my hero!

Will Robertson

Great for large numbers of levels, but quite poor for just a few (e.g., if you're labelling three or four lines on a plot). In fact, the code breaks for numberOfLevels < 3. But I don't believe that's the goal of the package, so that's okay.

Evan Variano

Colormap that unites grayscale and full color - hooray! - Where have you been all my life?!

Updates

1.0.0.0

input 'numberOfLevels' is now optional. Optimized for speed and readability by vectorizing code. Added the debug plotting options.

Thx to PederAxensten for suggestions and significant code snippet.
MATLAB Release Compatibility
Created with R2006a
Compatible with any release
Platform Compatibility
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