How do I create a logarithmic scale colormap or colorbar?

Question

MathWorks Support Team 2012-7-6

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https://ww2.mathworks.cn/matlabcentral/answers/100066-how-do-i-create-a-logarithmic-scale-colormap-or-colorbar

编辑： Rena Berman 2023-11-22

采纳的回答： MathWorks Support Team

I need to color 'surf' plots on a log scale and subsequently displace the log-based colorbar.

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Answer 1

MathWorks Support Team 2023-11-22

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https://ww2.mathworks.cn/matlabcentral/answers/100066-how-do-i-create-a-logarithmic-scale-colormap-or-colorbar#answer_1358242

编辑：MathWorks Support Team 2023-11-22

在 MATLAB Online 中打开

Please follow the steps below to create a log colobar in 'surf' plot:

% Plot the surface plot
[X, Y] = meshgrid(1:0.5:10,1:20);
Z = sin(X) + cos(Y);
figure;
surf(X, Y, Z)
% Show the colorbar
colorbar
% Set the log colobar
set(gca,'ColorScale','log')

Note: This feature was introduced in MATLAB R2018a.

For more information, refer to the following documentation page, "Axes Properties":

https://www.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#budumk7-ColorScale

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Answer 2

lvn 2023-11-9

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https://ww2.mathworks.cn/matlabcentral/answers/100066-how-do-i-create-a-logarithmic-scale-colormap-or-colorbar#answer_318663

编辑：Rena Berman 2023-11-22

在 MATLAB Online 中打开

set(gca,'ColorScale','log')

https://nl.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#budumk7-ColorScale

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Walter Roberson 2020-3-31

You can tell by the wording of the official answer that it was written for an older version of MATLAB.

Pat 2023-5-11

编辑：Walter Roberson 2023-9-5

Hi Kristoffer Walker,

If you still need assistance with this issue, please create a MathWorks Technical Support Case. We would be happy to help you out.

https://www.mathworks.com/support/contact_us.html

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Answer 3

Berthold Reisz 2019-3-15

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https://ww2.mathworks.cn/matlabcentral/answers/100066-how-do-i-create-a-logarithmic-scale-colormap-or-colorbar#answer_365558

在 MATLAB Online 中打开

Try the following:

% let A be your data
A = 100*rand(100,100);
% plot log10 of A
pcolor(log10(A))
% get the minimum and maximum value of A
c1 = min(min(A));
c2 = max(max(A));
% set limits for the caxis
caxis([log10(c1) log10(c2)]);
% preallocate Ticks and TickLabels
num_of_ticks = 5;
Ticks      = zeros(1,num_of_ticks);
TickLabels = zeros(1,num_of_ticks);
% distribute Ticks and TickLabels
for n = 1:1:num_of_ticks
    
    Ticks(n)      = log10(round(c2)/num_of_ticks*n);
    TickLabels(n) = round(c2)/num_of_ticks*n;
end
% set Ticks and TickLabels
colorbar('Ticks',Ticks,'TickLabels',TickLabels)