how to change the scale of an colour bar?

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Puspa patra 2018-8-9

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https://ww2.mathworks.cn/matlabcentral/answers/414155-how-to-change-the-scale-of-an-colour-bar

编辑： Robert U 2018-8-9

Hello, My plot range with variation from 0 to 3500, so I want to use an log scale colour bar instead of normal colour bar scale, so that I can show all the variations. please give some suggestion to change the colour scale of the colorbar into an log scale.

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Answer 1

Robert U 2018-8-9

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https://ww2.mathworks.cn/matlabcentral/answers/414155-how-to-change-the-scale-of-an-colour-bar#answer_332110

编辑：Robert U 2018-8-9

在 MATLAB Online 中打开

Hi Puspa patra,

I google'd it for you and found:

Depending on Matlab version, you can go with different approaches. Known from older versions (prior 2018a):

% Create testdata
Data=magic(100);
% Define color levels to create
nLvl = 9;
% get min and max values of Data
minData = min(min(Data));
maxData = max(max(Data));
% define colorbar values on log scale
c = logspace(log10(minData),log10(maxData),nLvl);
% plot data in log-scale according to defined log scale values 'c'
contourf(log(Data),log(c));
% Change colormap to "bone"
colormap(bone);
% define color axis scaling according to 'c'
caxis(log([c(1) c(end)]));
% open colorbar
colorbar('YTick',log(c),'YTickLabel',c);