MATLAB Answers

How do I create a logarithmic scale colormap or colorbar?

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MathWorks Support Team
MathWorks Support Team 2012년 7월 6일
편집: lvn 2021년 9월 17일 9:37
I need to color 'surf' plots on a log scale and subsequently displace the log-based colorbar.

채택된 답변

lvn
lvn 2018년 5월 4일
편집: lvn 2021년 9월 17일 9:37
  댓글 수: 7
Walter Roberson
Walter Roberson 2020년 3월 31일
You can tell by the wording of the official answer that it was written for an older version of MATLAB.

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추가 답변(2개)

Berthold Reisz
Berthold Reisz 2019년 3월 15일
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)

MathWorks Support Team
MathWorks Support Team 2020년 5월 14일
편집: MathWorks Support Team 2020년 5월 14일
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":
  댓글 수: 1
Samira Daneshgar
Samira Daneshgar 2017년 1월 12일
Hi, I would like to know how can I apply the same thing for the contourf. Thanks,

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