Color Palette Tables (.cpt) for Matlab

Create and apply GMT-style colormaps in Matlab

Description

This function creates and applies a colormap defined in a color palette table (.cpt) file. Color palette tables are used to define colormaps in the Generic Mapping Tools package (http://gmt.soest.hawaii.edu/). These files provide more flexible colormapping than Matlab's default schemes, including both discrete and continuous gradients, as well as easier direct color mapping.

For a complete description of the color palette table format, see the GMT documentation.

This package includes 20 standard GMT colormaps; please see the header of each file for copyright information. Many more color tables are available on the cpt-city website (http://soliton.vm.bytemark.co.uk/pub/cpt-city/index.html).

• MATLAB release: MATLAB 7.10 (R2010a)

[Claire]

Function works brilliantly!! Thanks so much!

[Kelly Kearney]

@Claire

Sorry, I always forget that roundn is part of the Mapping toolbox. Just replace the roundn call:

space = roundn(space, -3);

with

space = round(space*1e3)/1e3;

[Claire]

I don't have access to the "roundn" function. Is there a work around so that I can get your function working?

[Frank]

Excellent and very useful. Works as expected, and had no problems using with gradients provided from cpt-city (http://soliton.vm.bytemark.co.uk/pub/cpt-city/)

[Jesse Hansen]

Very useful for bathymetric mapping. Please note that there is a dependency on the mapping toolbox due to the use of the 'roundn' function. This could easily be replaced by 1 line of standard Matlab code.

[angela]

 

[Kelly Kearney]

@camilo melo,

I don't have R20011b, so I can't test it, but I can't think of any reason it wouldn't work in that version. Based on the error message you mention, my guess is you tried to call the function without any input arguments; it needs at least one (the name of the colormap).

[camilo melo]

hi, does this function works for MATLAB R2011b?? i tried to use it but got this error message Index exceeds matrix dimensions.

Error in cptcmap (line 123)
[blah, blah, ext] = fileparts(varargin{1});

[Felipe G. Nievinski]

Another one, trying

cptcmap('sst')

Just had to replace

if ~strcmp(varargin{1}(end-3:end), '.cpt') % without extension

for:

if (numel(varargin{1}) <= 4) || ~strcmp(varargin{1}(end-3:end), '.cpt') % without extension

[Felipe G. Nievinski]

Another one, trying

cptcmap('sst')

Just had to replace

if ~strcmp(varargin{1}(end-3:end), '.cpt') % without extension

for:

if (numel(varargin{1}) <= 4) || ~strcmp(varargin{1}(minend-3:end), '.cpt') % without extension

[Felipe G. Nievinski]

You might want to replace l.83:

cptpath = './cptfiles';

with:

cptpath = fullfile(fileparts(which('cptcmap')), 'cptfiles');

That way the source code needs not be modified when first downloading the package or later when moving the routine files around.

I was having problems trying

cptcmap('elevation')

where elevation.cpt was downloaded from cpt-city and placed in the cptpath; it turns out that l.98,

if exist(varargin{1}, 'file') % full filename and path given

would find this other file instead:

which elevation
C:\Program Files\MATLAB\R2009b\toolbox\map\map\elevation.m

You might want to replace the block l.98-111 with the following (minimally modified):

if ~strcmp(varargin{1}(end-3:end), '.cpt') % without extension
varargin{1} = [varargin{1} '.cpt'];
end
if exist(varargin{1}, 'file') % full filename and path given
filename = varargin{1};
else % only file name given
filename = fullfile(cptpath, varargin{1});
if ~exist(filename, 'file')
error('Specified .cpt file not found');
end
end

Finally, not sure why the __MACOSX subdirectory is being distributed.

[Felipe G. Nievinski]

Great idea, always wanted to make my matlab maps look like gmt's. Also thanks for pointing out to cpt-city, it's a great collection.

You might want to use the acknowledgement field in the FEX form, so that your submission is back-linked from related entries, e.g., 28982 and the ones linked from there.

[Kelly Kearney]

Marios,

If by the inverse colormap, you mean you want to flip the direction of the colors, then yes, use the 'flip' option:

cptcmap('GMT_seis', 'flip', true)

-Kelly

[Marios Karaoulis]

Hi. Very nice package. Is it possible to use the inverse colormap of GMT_seis.cpt?