MATLAB: Assigning black color to zero values of “imagesc” plot

Question

I want to use "imagesc" to plot the following matrix:

   A=[9 24 6 12 6;
      0 33 24 0 12;
      0 0 13 14 12;
      0 0 0 0 0];

I want to assign black color to 0 values and set the color bar from 6 to 33.

Answer 1

Try this:

A=[9 24 6 12 6;
  0 33 24 0 12;
  0 0 13 14 12;
  0 0 0 0 0];
imagesc(A);
cmap = jet(max(A(:)));
% Make values 0-5 black:
cmap(1:6,:) = zeros(6,3);
colormap(cmap);
colorbar