title: Get Map with specified boundary coordinates
body: <p>I want to get a map with RgoogleMaps from R, with a specific coordinates boundary.</p>
  
  <p>What I can call is GetMap, and specify a center, I must add a zoom level. Everything works fine, except that I am not getting an image map bounded with the coordinates I choose.</p>
  
  <p>Here's an example:</p>
  
  <pre><code>lat &lt;- c(44.49,44.5)                
  lon &lt;- c(11.33,11.36)               
  center = c(mean(lat), mean(lon))    
  zoom &lt;- 14                          
  mmap &lt;- GetMap(center = center, zoom=zoom, maptype= "satellite", destfile = "m.png") 
  </code></pre>
  
  <p>The problem is that only the center is passed as a parameter, and thus the whole image I see is dependant on the zoom level. So, I cannot really understand what are the boundaries of the image I get. What I want to do is to get an image bounded exactly with the coordinates I am defining. Is this possible (also with other map packages)?</p>