Conoscere le coordinate geografiche di un punto

[coniglio]

Ho trovato questo script che dovrebbe fare al caso mio... perchè su google maps va benissimo....

ma invece io non riesco a farlo funzionare...

in sostanza a me serve cliccare su un punto della mappa ed ottenere le coordinate...

come in questo esempio...

function initialize() {
  if (GBrowserIsCompatible()) {
    var map = new GMap2(document.getElementById("map_canvas"));
    map.setCenter(new GLatLng(37.4419, -122.1419), 13);

    GEvent.addListener(map,"click", function(overlay,latlng) {     
      if (latlng) {   
        var myHtml = "The GLatLng value is: " + map.fromLatLngToDivPixel(latlng) + " at zoom level " + map.getZoom();
        map.openInfoWindow(latlng, myHtml);
      }
    });
    map.addControl(new GSmallMapControl());
    map.addControl(new GMapTypeControl());
  }
}​ 

ma con le coordinate geografiche e non di pixel


in ogni caso ecco lo script che non riesco ad integrare... evidentemente non so come si usa... mi aiutate?

<?xml version="1.0" encoding="UTF-8"?>
<Module>

<ModulePrefs
    title="GPS Location" 
    description="Used to find GPS locations (Latitude &amp; Longitude) on a Google map."
    author="Jeff Grigg"
    author_email="jeffgrigg@charter.net"
    author_link="http://jeffgrigg.wordpress.com/"
    screenshot="http://gpsmaplet.googlecode.com/files/Screen%20Print.PNG"
    thumbnail="http://gpsmaplet.googlecode.com/files/Icon.PNG"
    height="200">
  <Require feature="sharedmap"/>
</ModulePrefs>

<Content type="html"><![CDATA[

<h2>GPS Location</h2>


Click on the map to show the GPS location (Latitude &amp; Longitude) of that location.</p>



Many thanks to [url="http://thomas.duebendorfer.ch/"]Thomas Duebendorfer[/url] for the Position Finder Maplet, which inspired this Maplet.</p>

<script>

  var gMap2 = new GMap2();

  function mapClick(gMarker, gLatLng) {
    if (gMarker) {
      displayMarkerPosition(gMarker);
    } else if (gLatLng) {
      createLocationMarker(gLatLng);
    }
  }

  function createLocationMarker(gLatLng) {
    var gMarker = new GMarker(gLatLng, {draggable: true, bouncy: true});
    gMap2.addOverlay(gMarker);

    displayMarkerPosition(gMarker);

    GEvent.addListener(gMarker, "dragstart", closeMapInfoWindow);

    GEvent.addListener(gMarker, "dragend", function() {
      displayMarkerPosition(gMarker);
    });
  }

  function closeMapInfoWindow() {
    gMap2.closeInfoWindow();
  }

  function displayMarkerPosition(gMarker) {
    GAsync(gMarker, 'getPoint', gMap2, 'getBounds', 'getSize', function(gLatLng, gLatLngBounds, gSize) {
      gMarker.openInfoWindowHtml(gpsString(gLatLng, gLatLngBounds, gSize));
    });
  }

  function gpsString(gLatLng, gLatLngBounds, gSize) {
    var ne = gLatLngBounds.getNorthEast();
    var sw = gLatLngBounds.getSouthWest();

    var degreesPerPixel = (ne.lat() - sw.lat()) / gSize.height;
    var goodDigits = Math.ceil(- Math.log(degreesPerPixel) / Math.log(10))
 
    var roundedLatLng = roundGLatLng(gLatLng, goodDigits);
 
    return "GPS: " + roundedLatLng.lat() + ", " + roundedLatLng.lng();
  }

  function roundGLatLng(gLatLng, goodDigits) {
    return new GLatLng(roundNumber(gLatLng.lat(), goodDigits), roundNumber(gLatLng.lng(), goodDigits));
  }

  function roundNumber(number, goodDigits) {
    var power = Math.pow(10, Math.ceil(goodDigits));
    return Math.round(number * power) / power;
  }

  GEvent.addListener(gMap2, "click", mapClick);

</script>

]]></Content>
</Module>