title: Rotating Basemap Meridian labels on x-axis
body: <p>Is it possible to rotate the meridian labels so that they are no longer overlapping? See the image for an example below.  I don't want to reduce the number of meridian lines.</p>
  
  <p>I've tried: </p>
  
  <pre><code>ax = plt.gca()
  ax.set_xticklabels( meridians, rotation=45 )
  </code></pre>
  
  <p>This doesn't do anything in Basemap though.  </p>
  
  <p><img src="https://i.stack.imgur.com/YauzL.png" alt="enter image description here"></p>