title: Matlab imagesc plotting nan values
body: <p>When using imagesc to visualize data that contains NaN values, Matlab treats them as the minimum value(in gray it paints them black, jet - blue, etc). the jet colormap doesn't contain neither black nor white. is it possible to display the nan values as black/white?
  for example:</p>
  
  <pre><code>data = [0 0 0 ; .5 .5 .5 ;1 1 1;nan nan nan];
  </code></pre>
  
  <p>should yield blue-green-red-black strips.</p>
  
  <p>Thanks</p>