title: Area select event for R leaflet in shiny
body: <p>I've played with the mouse click event in leaflet using the following code:</p>
  
  <pre><code>mymap=leaflet()
  selected_site=eventReactive(input$mymap_marker_click,{
        event &lt;- input$mymap_map_marker_click
        return(mydt[Long==event$lng &amp; Lat==event$lat,get("sites")])
      })
  </code></pre>
  
  <p>to display a plot from a <code>data.table</code>  after a click on a point of the map. 
  Now, I'd like to select an entire area then display data binding to it.</p>
  
  <p>In other terms, I'd like to select not a couple of (Lat,Long) but a series of (Lat1, Long1)....(Latn,Longn)</p>
  
  <p>Is there a mean to do it in leaflet ?</p>
  
  <p>Thanks in advance,</p>