Get Colormap Values Corresponding to Array Values
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Dear Matlab Community,
Currently I am trying to visualize neuroimaging data and have thus run into the following problem:
I have an array of 1990 values, which I want to plot in different colors on a continuous colorbar. So all I would require is the information on how I can get a matrix with RGB triplets corresponding to the data in my array. I have already tried the following:
c = jet(cvals)
Which yields in the following code:
Error using /
Matrix dimensions must agree.
Error in jet (line 23)
u = [(1:1:n)/n ones(1,n-1) (n:-1:1)/n]';
Any help would be greatly appreciated.
Thank you!
2 个评论
Yazan
2021-8-13
What version of Matlab do you have? When run on 2021a, no errors were received.
Hannah_Mad
2021-8-13
采纳的回答
% rand cvars
cvars = randi([10 450], [128, 1]);
% You need to specify the number of colors to represent these cvars
n = 512;
cmap = jet(n);
% cvars has a different range from cmap range (1:512), so you have to map
% it. (similar to imagesc)
cvars_map = (cvars - min(cvars))/(max(cvars)-min(cvars)) * (n-1) + 1;
% Now find the color of i-th cvars
i = 10;
cvars(i)
cvars_map(i) % mapped cvars
cmap(cvars_map(i), :) % corresponding color
3 个评论
Hannah_Mad
2021-8-13
Chunru
2021-8-13
cvars is considered continuous (the code above just use the min and max of cvars). This continous values are then divided into n intervals. Each interval is then mapped into 1 of the n colors.
If you only have 70 unique values, then they correspond to 70 unique colors (out of n=512) colors. Some other colors will not really used.
If you do want to have each unique value correspond to a color, it can be also down. But you need to specify which color map you want to use.
Hannah_Mad
2021-8-13
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