title: In R, find the polygon containing a point - Shapefile
body: <p>I have a shapefile and I would like to find the polygon containing a list of points. For example,</p>
  
  <pre><code>rio &lt;- readShapeSpatial("setores_rio.shp")  
  bairrorio.fort&lt;- fortify(rio , region = "neighborhood")
  
  head(bairrorio.fort)
     long       lat order  hole piece          group           id
  1 -43.17769 -22.91814     1 FALSE     1 330455705001.1 330455705001
  2 -43.17771 -22.91814     2 FALSE     1 330455705001.1 330455705001
  3 -43.17771 -22.91808     3 FALSE     1 330455705001.1 330455705001
  4 -43.17793 -22.91811     4 FALSE     1 330455705001.1 330455705001
  5 -43.17811 -22.91768     5 FALSE     1 330455705001.1 330455705001
  6 -43.17802 -22.91766     6 FALSE     1 330455705001.1 330455705001
  </code></pre>
  
  <p>Assume that p = c(long, lat) is a point with lat long localization. I would like to find the id(neighborhood) (see bairrorio.fort) containing the point p. </p>