Slightly modify lat/lng for gmap api v3

Have a quick question. On my website I have a form that allows users to input their city, state, and country. This information is converted to $lat and $lng, which is used to create a marker on a google map. Problem is, I have multiple users that select the same city. Clustering is a HUGE pain... to be honest, I can't seem to find a good tutorial and I'm feeling a bit hopeless.

So I thought I'd just modify each $lat and $lng slightly. For example, this is the info I get for Travis AFB, CA: lat="38.263065" lng="-121.949699". Wondering if it's possible to add a bit of code that might let me modify those last bits. Any suggestions???

Here's how I geocode $address (combination of $city, $state, $country):

$geocodestring=file_get_contents('http://maps.googleapis.com/maps/api/geocode/json?sensor=false&address=' . urlencode($address) );
$geocodedinfo=json_decode($geocodestring);


$lat = $geocodedinfo->results[0]->geometry->location->lat;
$lng = $geocodedinfo->results[0]->geometry->location->lng;

And that information goes into my SQL database. This is the code that actually creates the map (pretty straightforward).

function load() {
  if (GBrowserIsCompatible()) {
 var map = new GMap2(document.getElementById("map"));
 map.addControl(new GSmallMapControl());
 map.addControl(new GMapTypeControl());
 map.setCenter(new GLatLng(47.614495, -122.341861), 2);
 map.enableScrollWheelZoom();

GDownloadUrl("world_xml.php", function(data) {
   var xml = GXml.parse(data);
   var markers = xml.documentElement.getElementsByTagName("marker");
   for (var i = 0; i < markers.length; i++) {
  var first_name = markers[i].getAttribute("first_name");
  var last_name = markers[i].getAttribute("last_name");
  var email = markers[i].getAttribute("email");
  var affiliation = markers[i].getAttribute("affiliation");
  var status = markers[i].getAttribute("status");
  var service = markers[i].getAttribute("service");
  var rank = markers[i].getAttribute("rank");
  var specialty = markers[i].getAttribute("specialty");
  var city = markers[i].getAttribute("city");
  var state = markers[i].getAttribute("state");
  var country = markers[i].getAttribute("country");
  var point = new GLatLng(parseFloat(markers[i].getAttribute("lat")),
        parseFloat(markers[i].getAttribute("lng")));
  var marker = createMarker(point, rank, first_name, last_name, email, affiliation, status, service, specialty, city, state, country);
  map.addOverlay(marker);
   }
 });
  }
}

function createMarker(point, rank, first_name, last_name, email, affiliation, status, service, specialty, city, state, country) {
  var marker = new GMarker(point);
  var html = "" + rank + " " + first_name + " " + last_name + " 
" + service + ", " + status + " 
" + specialty + " 
" + affiliation + " 
" + city + ", " + state + " " + country + " 
" + email + " 
" + " ";
  GEvent.addListener(mar开发者_JAVA百科ker, 'click', function() {
 marker.openInfoWindowHtml(html);
  });
  return marker;
}

Any help/suggestions would be much appreciated!!!

Jeremy

markerclusterer for v2 may solve your problem.

Find code and examples here

http://google-maps-utility-library-v3.googlecode.com/svn/tags/markerclusterer/1.0/