How to convert String to CLLocationDegrees Swift 2 - ios

Question

I am trying to convert a String that I am retrieving from Firebase and adding it as several annotations on Google Maps. Unfortuanately, my app is crashing whenever it goes through the current code:
ref = FIRDatabase.database().reference()
ref.child("Locations").observeSingleEventOfType(.Value, withBlock: { (snapshot) in
let lat = (snapshot.value!["Latitude"] as! NSString).doubleValue
let lon = (snapshot.value!["Longitude"] as! NSString).doubleValue
let complainLoc = CLLocationCoordinate2DMake(lat, lon)
let Coordinates = CLLocationCoordinate2D(latitude: lat, longitude: lon)
})
My JSON Tree
My Code Block Which Crashes
Here is the code I used for saving data to Firebase
FIRDatabase.database().reference().child("Location").child(FIRAuth.auth()!.currentUser!.uid).setValue(["Latitude": locationManager.location!.coordinate.latitude, "Longitude": locationManager.location!.coordinate.longitude])

Answer 1

SWIFT 5
let dbLat = Double(latStr) // Convert String to double
let dbLong = Double(longStr)
Use latitude and longitude
let center = CLLocationCoordinate2D(latitude: dbLat! , longitude: dbLong! )
let pointAnnotation = MKPointAnnotation()
pointAnnotation.coordinate = CLLocationCoordinate2D(latitude: dbLat!, longitude:dbLong!)

Answer 2

Make sure when you are saving the values of lat and lon to the database you are saving them as Float or Double..
For retrieving use :
ref = FIRDatabase.database().reference()
ref.child("Locations").observeEventType(.Value, withBlock: { (snapshot) in
if snapshot.exists(){
if let locationDictionary = snapshot.value as [String : AnyObject]{
for each in locationDictionary{
//each will bring you every location dictionary in your database for your every user
let lat = each.value!["Latitude"] as! CLLocationDegrees
let lon = each.value!["Longitude"] as! CLLocationDegrees
let userId = each.key as! String
let complainLoc = CLLocationCoordinate2DMake(lat, lon)
let Coordinates = CLLocationCoordinate2D(latitude: lat, longitude: lon)
//Every time this for loop complete's itself it will generate a new set of Coordinates for each user
}
}
}
})
EDIT:
Updated code for Firebase 6 and Swift 5
let ref = self.ref.child("Locations")
ref.observeSingleEvent(of: .value, with: { snapshot in
let allLocations = snapshot.children.allObjects as! [DataSnapshot]
for location in allLocations {
let lat = location.childSnapshot(forPath: "Latitude").value as! CLLocationDegrees
let lon = location.childSnapshot(forPath: "Longitude").value as! CLLocationDegrees
let userId = location.key
let locCoord = CLLocationCoordinate2DMake(lat, lon)
let coordinates = CLLocationCoordinate2D(latitude: lat, longitude: lon)
}
})
note that self.ref points to my Firebase root ref.