Why iOS CLLocation shows incorrect values? - ios

Question

I'm trying to calculate distance between 2 coordinates. For this I do:
func setupLocationManager() {
if CLLocationManager.authorizationStatus() == .NotDetermined {
locationManager.requestWhenInUseAuthorization()
}
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.startUpdatingLocation()
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let latitude = locations.last?.coordinate.latitude
let longitude = locations.last?.coordinate.longitude
let myLocation = CLLocation(latitude: latitude!, longitude: longitude!)
let targetLocation = CLLocation(latitude: 41.4381022, longitude: 46.604910)
let distance = myLocation.distanceFromLocation(targetLocation)
print(distance)
}
I'm checking in Google Maps there are 13 km distance! But my app shows me 2-3 km!
How can I improve that?

Answer 1

Google maps gives you the route distance between two locations, CLLocation gives you the birds-eye distance between two locations.
From the documentation:
This method measures the distance between the two locations by tracing
a line between them that follows the curvature of the Earth. The
resulting arc is a smooth curve and does not take into account
specific altitude changes between the two locations.

Answer 2

Here is an example based on a working GPS app.
import CoreLocation
public class SwiftLocation: NSObject, CLLocationManagerDelegate {
private let locationManager = CLLocationManager()
private var latestCoord: CLLocationCoordinate2D
init(ignore:String) {
locationManager.requestAlwaysAuthorization()
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.startUpdatingLocation()
latestCoord = locationManager.location!.coordinate
super.init()
locationManager.delegate = self
}
private func locationManager(manager: CLLocationManager, didUpdateToLocation newLocation: CLLocation, fromLocation oldLocation: CLLocation) {
latestCoord = manager.location!.coordinate
}
public func getLatest() -> CLLocationCoordinate2D {
return latestCoord
}
}