MATLAB: How to add more colormap marker spots

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How do I increase the detail of my colormap? I want to add even more marker spaces than given.

The colormap editor only has about 64 bits for a colormap such as jet. How do I add more?

Best Answer

One way to do this is to create your own custom colormap with more elements.

Another option is to define the colormap with more colors. For example, the jet colormap can take as input the number of entries (or colors) desired.

>> c = jet(500)
>> colormap(c)

For more information, please see the documentation page for "jet".

https://www.mathworks.com/help/matlab/ref/jet.html

This can be done with the other MATLAB colormap arrays as well.

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MATLAB: Setting Default Properties for a Colorbar Label

As of MATLAB R2017b, it is not possible to set property defaults that apply to the colorbar label.

As a workaround, you can set the properties of the colorbar label after the colorbar has been defined. For example, you can use the following code to set the interpreter for the colorbar label:

>> figure;
>> cb=colorbar;
>> cb.Label.Interpreter='latex';

MATLAB: How to set the colorbar to have a limited number of colors

For MATLAB versions R2014b and later:

As of MATLAB R2014b, you can accomplish this with the 'colormap' function. You can use the 'colormap' function to customize the range of colors that gets displayed. You can create a completely custom colormap by specifying each RGB value:

map = [0, 0, 0.3;
  0, 0, 0.4;
  0, 0, 0.5;
  0, 0, 0.6;
  0, 0, 0.8;
  0, 0, 1.0];
colormap(map)

Or if you would like a starting point for creating the values in 'map', you can use values from one of the built-in colormaps:

>> map = parula(64)

For MATLAB versions R2014a and earlier:

The ability to set the number of colors in a colorbar is not directly available in MATLAB.

However, this is possible by changing the 'CData' property of the image that resides in the COLORBAR axes, as shown in the example below:

mx = peaks(100);
numberOfColors = 5;
% This value will be used in the code below to set the number of colors as desired
nc = numberOfColors-1;
% Use this syntax of contourf to select number of contours
[c,h, cf] =contourf(mx,nc);
cb = colorbar;
% Find the image inside the colorbar object,
% then find the limits of the data to set colorbar axes
i = findobj(cb,'type','image');
minVal = min(mx(:));
maxVal = max(mx(:));
% Set the colorbar's CData to the desired number of intervals
set(i,'cdata',[0:64/nc:64]','YData',[minVal maxVal]);

Finally, set the tick marks of the colorbar:

% Option 1: Set the colorbar ticks to sit in the center of the color bins
set(cb,'yLim',[minVal maxVal],'ytick',[minVal:(maxVal-minVal)/(nc):maxVal]');   
% Option 2: Set the ticks to sit both at the centers and at the edges of the color bins
%set(cb,'yLim',[minVal maxVal],'ytick',[minVal:(maxVal-minVal)/(2*nc):maxVal]');

You can refer to the documentation for more details and examples:

https://www.mathworks.com/help/matlab/ref/colormap.html

Best Answer

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MATLAB: Setting Default Properties for a Colorbar Label

MATLAB: How to set the colorbar to have a limited number of colors

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