MATLAB Answers


Assining fixed color for zero value

Asked by Sarem.N
on 29 Oct 2019
Latest activity Commented on by Sarem.N
on 29 Oct 2019
i have a 2D matrix A(i,j). each value in this matrix can be the integers between 1:n for examle. some cells are equal to zero and i need an image plot of A but with black color for zero values. is it possible in matlab?


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1 Answer

Answer by Adam
on 29 Oct 2019
Edited by Adam
on 29 Oct 2019
 Accepted Answer

Define a colourmap of size n, assuming n is not huge, and then add black to the front of it
n = 7;
colourmap = [0 0 0; parula( n )];
Then, e.g.
myData = randi(n, 20 ) - 1;
figure; imagesc( myData );
colormap( colourmap )
caxis( [-0.5 n + 0.5] )

  1 Comment

Thats exactly what i want. Thanks a lot

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