var map;
    var InnVicGeoXML; 
    var TheartsGeoXML; 
    var OutdooractivitiesGeoXML; 
    var HistoricalGeoXML; 
    var RestaurantsGeoXML; 
    var ShoppingGeoXML; 

    // initialize state variables
    var TheartsToggleState = 0;
    var OutdooractivitiesToggleState = 0;
    var HistoricalToggleState = 0;
    var RestaurantsToggleState = 0;
    var ShoppingToggleState = 0;

    function initialize_google_map()
    {
      if (GBrowserIsCompatible())
      {
        // initialize KML overlay 
        InnVicGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/innvic.kml");
        TheartsGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/thearts.kml");
        OutdooractivitiesGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/outdooractivities.kml");
        HistoricalGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/historical.kml");
        RestaurantsGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/restaurants.kml");
        ShoppingGeoXML = new GGeoXml("http://www.innvictoria.com/google-maps/shopping.kml");

        // initialize map and add the default area attractions overlay
        map = new GMap2(document.getElementById("map_canvas")); 
        map.setCenter(new GLatLng(43.2649,-72.600894), 14); 
        map.addControl(new GLargeMapControl());
        map.addControl(new GMapTypeControl());

        RestaurantsToggleState = 1;
        map.addOverlay(RestaurantsGeoXML);
        map.addOverlay(InnVicGeoXML);
      }
    } 

    function TurnOnThearts()
    {
      if(0 == TheartsToggleState)
      {
        map.addOverlay(TheartsGeoXML);
        TheartsToggleState = 1;
      }
    }

    function TurnOffThearts()
    {
      if(1 == TheartsToggleState)
      {
        map.removeOverlay(TheartsGeoXML);
        TheartsToggleState = 0;
      }
    }

    function TurnOnOutdooractivities()
    {
      if(0 == OutdooractivitiesToggleState)
      {
        map.addOverlay(OutdooractivitiesGeoXML);
        OutdooractivitiesToggleState = 1;
      }
    }

    function TurnOffOutdooractivities()
    {
      if(1 == OutdooractivitiesToggleState)
      {
        map.removeOverlay(OutdooractivitiesGeoXML);
        OutdooractivitiesToggleState = 0;
      }
    }

    function TurnOnHistorical()
    {
      if(0 == HistoricalToggleState)
      {
        map.addOverlay(HistoricalGeoXML);
        HistoricalToggleState = 1;
      }
    }

    function TurnOffHistorical()
    {
      if(1 == HistoricalToggleState)
      {
        map.removeOverlay(HistoricalGeoXML);
        HistoricalToggleState = 0;
      }
    }
    function TurnOnRestaurants()
    {
      if(0 == RestaurantsToggleState)
      {
        map.addOverlay(RestaurantsGeoXML);
        RestaurantsToggleState = 1;
      }
    }

    function TurnOffRestaurants()
    {
      if(1 == RestaurantsToggleState)
      {
        map.removeOverlay(RestaurantsGeoXML);
        RestaurantsToggleState = 0;
      }
    }
    function TurnOnShopping()
    {
      if(0 == ShoppingToggleState)
      {
        map.addOverlay(ShoppingGeoXML);
        ShoppingToggleState = 1;
      }
    }

    function TurnOffShopping()
    {
      if(1 == ShoppingToggleState)
      {
        map.removeOverlay(ShoppingGeoXML);
        ShoppingToggleState = 0;
      }
    }