title: Find in which country each point-coordinate belongs to
body: <p>I have a data frame with lat/lon coordinates:</p>
  
  <pre><code>head(COORD)
     LAT   LON 
  1  69.34 16.17  
  2  69.20 17.92   
  3  69.59 17.87 
  4  69.17 18.52  
  5  69.42 18.95 
  6  69.22 18.91 
  </code></pre>
  
  <p>I would like to to retrieve the country name of each point and add it as a third column.
  Maybe using <code>which</code> in combination with <code>map</code> to retrieve in which polygon the points are but I was not able to figure out how.</p>