title: find area of interests around 5 square miles
body: <p>In web <code>gis</code> class using <code>Postgis</code>, I want to find area of interests around 5 square miles of a selected point.I have to use <code>ST_within</code>.</p>
  
  <p>This is the query I written:</p>
  
  <pre><code>select hw1.route,count(*) from hw as hw1, hw as hw2,aoi where 
  st_within(hw1.the_geom,aoi.the_geom) group by hw1.route;
  </code></pre>