title: How to refresh all markers in google maps v3?
body: <p>I want to be able to refresh all the markers every minute. This means the existing markers should be deleted parse again the data from the xml file and draw them again on the map. It apears that <code>map.clearOverlays();</code> isn't working on v3 and I should interate among the markers to delete them some how. </p>
  
  <p>Which is the right syntax to delete the existing markers and load new ones on a given time interval?</p>