title: plot extra circle on a Matlab figure
body: <p>I'm plotting rose diagrams using Matlab7. And I would like to add an extra red circle on the rose diagram. </p>
  
  <pre><code>rose(data,nbins);
  hold on
  </code></pre>
  
  <p>I tried the function <code>pdecirc</code> but it doesn't work. Anyonce can give me a clue?</p>
  
  <p>Thank you</p>