title: timed delayed use of qmap() in R?
body: <p>G'day,</p>
  
  <p>I am trying to learn how to use the ggmap package in R, but am getting stuck at the very beginning. All I am trying to do is use the qmap() function to download maps, but I am getting some very strange results. I have tried:</p>
  
  <pre><code>library(ggmap)
  aus&lt;- qmap('australia')
  aus&lt;- qmap('australia', zoom = 5)
  </code></pre>
  
  <p>and number of other locations and things. Sometimes a map is downloaded, but more often than not I get the following error message:</p>
  
  <pre><code>Error in download.file(url, destfile = destfile, quiet = !messaging, mode = "wb"): 
    cannot open URL 'http://maps.googleapis.com/maps/api/staticmap?center=adelaide&amp;zoom=6&amp;size=%20640x640&amp;scale=%202&amp;maptype=terrain&amp;sensor=false'
  In addition: Warning message:
  In download.file(url, destfile = destfile, quiet = !messaging, mode = "wb") :
    cannot open: HTTP status was '403 Forbidden' 
  </code></pre>
  
  <p>It will work correctly one time then 5 secs later when I try it again with the exact some code it wont work.  </p>
  
  <p>From repeatedly using this function it seems like there is a time delay between its successful use. I have timed how long I have to wait between between successful uses, and it seems that 1 min is this thresh-hold. Also, every time I try to use the function, whether it is successful or not, it resets this 1 minute waiting time. </p>
  
  <p>Do places like google restrict how often you can download stuff? This is a little frustrating if I want to quickly check if a map is the appropriate size, etc. Has anyone had the same experience, know what I might be doing wrong, or know a way around this issue? </p>
  
  <p>Thanks in advance for your time and help!</p>
  
  <p>Cheers,
  Adam</p>