title: Generate Contour Given X, Y and Z vectors
body: <p>Given 3 vector-pair, <code>X</code>, <code>Y</code> and <code>Z</code>, how to generate the contour? I understand that we need to make use of the <a href="http://www.mathworks.com/access/helpdesk/help/techdoc/ref/contour.html" rel="nofollow noreferrer"><code>contour</code></a> plot. But the thing is that we need to pass in a 2x2 matrix for this argument, which presumably, is a matrix of Z corresponding to each X,Y pair. But this would mean that I have to go extra miles to create such a matrix by using <code>griddata</code> interpolation first before talking about contour generation.</p>
  
  <p>Is there any other more succinct method?</p>