var map;
  function initialize() {
	var mapDiv = document.getElementById('map-canvas');
	map = new google.maps.Map(mapDiv, {
	  center: new google.maps.LatLng(-23.556068,-46.78099),
	  zoom: 16,
	  mapTypeId: google.maps.MapTypeId.ROADMAP
	});
  
	google.maps.event.addListenerOnce(map, 'tilesloaded', addMarkers);
  
  }
  
  function addMarkers() {
	var bounds = map.getBounds();
	var southWest = bounds.getSouthWest();
	var northEast = bounds.getNorthEast();
	var lngSpan = northEast.lng() - southWest.lng();
	var latSpan = northEast.lat() - southWest.lat();

	  var latLng = new google.maps.LatLng(-23.556068,-46.78099);
	  var marker = new google.maps.Marker({
		position: latLng,
		map: map
	  });

  }
  

  google.maps.event.addDomListener(window, 'load', initialize);