Get Colormap Values Corresponding to Array Values
126 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
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 commentaires
Yazan
le 13 Août 2021
What version of Matlab do you have? When run on 2021a, no errors were received.
Réponse acceptée
Chunru
le 13 Août 2021
% 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 commentaires
Chunru
le 13 Août 2021
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.
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Colormaps dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!