     func buildingChanged (note:NSNotification) {
         //if let object:NSDictionary = (note.object as! NSDictionary) {
         if let object:NSDictionary = note.userInfo {
+            self.building = nil
             if let building:String = object["building"] as? String {
                 self.building = building
             }

    
    func setLocationContext(context:NSMutableDictionary) {
        if let latitude = latitude {
            if isnan(latitude) {
                return
            }
            context["latitude"] = latitude
            if let longitude = longitude {
                context["longitude"] = longitude

    func locationChanged (note:NSNotification) {
        if let object = note.userInfo {
            if let current = object["current"] as? HLPLocation {
                self.latitude = nil
                self.longitude = nil
                self.floor = nil
                if (!isnan(current.lat) && !isnan(current.lng)) {
                    self.latitude = current.lat
                    self.longitude = current.lng
                }
                if (!isnan(current.floor)) {
                    self.floor = Int(round(current.floor))
