title: Python: copy basemap or remove data from figure
body: <p>I want to use a basemap figure as a background and plot things ontop. As the generation of the basemap figure (a polar stereographic plot) is quite time intensive I only want to do this once. </p>
  
  <p>The second step would be to draw some wind barbs on this plot and some other wind barbs on the same plot, but without the first set of barbs.</p>
  
  <p>Now either I copy the background image and then draw two different images or I can remove the first set of barbs and then draw the second, I don't mind which way to go.</p>
  
  <p>Unfortunately my brain is not helping me today and I am getting nowhere. I would be grateful for any tips.</p>