title: Gnuplot , pm3d with contour lines
body: <p>i am 3d plotting a matrix with some values, and i need to add contour lines to the plot, is there a simple gnuplot command to do this? </p>
  
  <p>I tried the command: "set contour base" but only 1 line came up, i think it should be many lines. See matlab picture</p>
  
  <p>When i plot it in gnuplot i only get 1 contour line in the top left corner.But everything else is correct.</p>
  
  <p>My goal is to get it to look like in matlab like this <a href="http://i.stack.imgur.com/p4ueb.png" rel="nofollow">Matlabplot</a></p>
  
  <p>I also found this example: see link in comments (dont have enough rep), but i dont understand where i should put in the data values from test.txt</p>
  
  <h1>test.txt</h1>
  
  <p><a href="https://drive.google.com/file/d/0B9CEsYCSSZUSOTVwSWdJbVVzdUU/view?usp=sharing" rel="nofollow">test.txt</a></p>
  
  <h1>gnuplot commands</h1>
  
  <pre><code>set view map
  set yrange [0:30]
  set xrange [0:30]
  set dgrid3d 100,100,4
  set contour base
  splot 'test.txt' u 1:2:3 w pm3d
  </code></pre>