I use Google maps, I mark areas on the maps like that:
var a
Did you add
zoom: 10,
center: myLatlng,
for you Marker Object
(or)
// map: an instance of GMap3
// latlng: an array of instances of GLatLng
var latlngbounds = new google.maps.LatLngBounds();
latlng.each(function(n){
latlngbounds.extend(n);
});
map.setCenter(latlngbounds.getCenter());
map.fitBounds(latlngbounds);