title: R ggmap: Why can I create rectangular maps using the filename attribute, but not use them in a plot?
body: <p>I would like to create a world map in R. I'm somewhat familiar with <code>ggmap</code>, so I tried something like this:</p>
  
  <pre><code>ggmap(get_googlemap(center=c(83,25),
                      zoom=1, scale=4, filename="world", size=c(640,300)))
  </code></pre>
  
  <p>It does work fine as far as the <code>world.png</code> is concerned.</p>
  
  <p><img src="https://i.stack.imgur.com/VGm0X.png" alt="The world.png output"> </p>
  
  <p>I was actually quite happy to have found a workaround for <code>ggmap</code>'s "can't show anything above 80° latitude" issue, due to which it's more or less impossible to create maps of the whole world.</p>
  
  <p>However, in R itself, that is in the plots, the map looks not at all the way it's supposed to:
  <img src="https://i.stack.imgur.com/d0uF6.png" alt="Failed R map plot"></p>
  
  <p>This only happens when the map is rectangular (when the <code>size</code> attribute is set accordingly), and not square (as would be the default).</p>
  
  <p>Why's that? Is there any chance that this issue will be resolved in the future?
  And what's the quickest way from here to a proper world map?</p>