title: How do I get Gnuplot to "fill" out of range matrix-points with color of boundary?
body: <p>I have a rather specific problem. I want to plot a electronic difference density using <strong>splot</strong>. The gridfile contains values from around -5 to up to 25. However, I am only interested in small values to find nodelines. So I would like to set palette such, that everything that is smaller/larger than the lower/upper boundary has the boundary color.
  Here is what I use:</p>
  <pre><code>set key off
  set view map
  set palette defined (-0.01 'blue', 0 'white', 0.01 'red')
  splot [][][-0.01:0.01] 'gridfile.dat' matrix with points pointtype 5 palette
  </code></pre>
  <p>That gives me almost what I want - but instead of coloring the out of range points with the colors of the boundaries gnuplot just does nothing (so I get the color of the background there).</p>
  <p>I tried fiddling around with cbrange, because according to the manual, that should do what I need:</p>
  <blockquote>
  <p>Cbrange</p>
  <p>The set cbrange command sets the range of values which are colored using the current palette by styles with pm3d, with image and with palette. Values outside of the color range use color of the nearest extreme.</p>
  </blockquote>
  <p>However, that has not worked so far and I am running out of ideas (and out of possible google-searches).</p>
  <p>Does anybody know how I could solve this?</p>