title: update a figure made with imshow(), contour() and quiver()
body: <p>I'd like to know whether one can update a contour done with <code>contour()</code>, a vector field done with <code>quiver()</code>, and an image done with <code>imshow()</code>, without actually having to call those functions again or creating a new figure, axes etc. In other words, is it possible (and is it usually what people do) to update those elements of a figure without re-calling the routines.</p>
  
  <p>I've tried solutions based on <code>set_array()</code> and <code>pyplot.draw()</code> but I can't make it work for the vector field and contour plot.</p>