为什么iOS CLLocation显示不正确的值？

Question

我正在尝试计算2个坐标之间的距离。 为此，我这样做：

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)
}

我在检查Google地图是否有13公里的距离！ 但是我的应用显示了2-3公里！

我该如何改善呢？

Answer 1

Google地图为您提供两个位置之间的路线距离， CLLocation为您提供两个位置之间的鸟瞰距离。

从文档中 ：

该方法通过跟踪两个位置之间遵循地球曲率的直线来测量两个位置之间的距离。 产生的弧线是平滑的曲线，并且没有考虑两个位置之间的特定高度变化。

Answer 2

这是一个基于运行中的GPS应用程序的示例。

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
    }
}