如何计算我当前位置和MapView中其他Pins之间的距离

Question

I am new to Swift and I need to calculate the nearest places around my current location. Would you advice me which function should I use to calculate the distance between my location and the nearest around me. I have to display the distance and the places in the app,so that the user can choose which one fits best for him.I think I should use latitude and longitude coordinates which can be compared with mine. I also found out that I have to use distanceFromLocation , but I do not know how and I would be glad if someone provide me with an example which I can use for my code. My code so far is:

 class ViewThree: UIViewController, CLLocationManagerDelegate{
@IBOutlet weak var SegmentControl: UISegmentedControl!
@IBOutlet weak var Mapview: MKMapView!


var manager =  CLLocationManager()
var receiveImeNaSladkarnica: String = ""
var KordaA: String = ""
var KordaB: String = ""
var PodImeNaObekt: String = ""

  override func viewDidLoad() {
super.viewDidLoad()


    let pinLocation: CLLocationCoordinate2D = CLLocationCoordinate2DMake((KordaA as NSString).doubleValue,(KordaB as NSString).doubleValue)
    let objectAnn = MKPointAnnotation()
    objectAnn.coordinate = pinLocation
    objectAnn.title = receiveImeNaSladkarnica
    objectAnn.subtitle = PodImeNaObekt
    self.Mapview.addAnnotation(objectAnn)

 }

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

@IBAction func Directions(sender: AnyObject) {
    UIApplication.sharedApplication().openURL(NSURL(string: "http://maps.apple.com/maps?daddr=\((KordaA as NSString).doubleValue),\((KordaB as NSString).doubleValue))")!)



}

@IBAction func MapType(sender: AnyObject) {
    if (SegmentControl.selectedSegmentIndex == 0){
        Mapview.mapType = MKMapType.Standard
    }
    if (SegmentControl.selectedSegmentIndex == 1){
        Mapview.mapType = MKMapType.Satellite
    }


}

@IBAction func LocateMe(sender: AnyObject) {
    manager.delegate = self
    manager.desiredAccuracy = kCLLocationAccuracyBest
    manager.requestWhenInUseAuthorization()
    manager.startUpdatingLocation()

    Mapview.showsUserLocation = true



}
func  locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let userlocation: CLLocation = locations[0] as CLLocation
    manager.stopUpdatingLocation()
    let location = CLLocationCoordinate2D(latitude: userlocation.coordinate.latitude, longitude: userlocation.coordinate.longitude)
    let span = MKCoordinateSpanMake(0.5, 0.5)
    let region = MKCoordinateRegion(center: location, span: span)
    Mapview.setRegion(region, animated: true )
}

Answer 1

I had the same scenario with an other app.

Within the CLLocation object, there is an instance function:

func distanceFromLocation(location: CLLocation) -> CLLocationDistance

//Get your two locations that you want to calculate the distance from:

let userLocation: CLLocation = ...
let locationToCompare: CLLocation = ...

// Returned value is in meters
let distanceMeters = userLocation.distanceFromLocation(locationToCompare)

// If you want to round it to kilometers
let distanceKilometers = distanceMeters / 1000.00

// Display it in kilometers
let roundedDistanceKilometers = String(Double(round(100 * distanceKilometers) / 100)) + " km"

UPDATED

For your use case

let locations = ... // All locations you want to compare

for location in locations {

    let distanceMeters = userLocation.distanceFromLocation(location)

    if distanceMeters > 5000 { // Some distance filter
          // Don't display this location
    } else {
          // Display this location
    }

}

MY CODE: IMPROVED

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    let userlocation:CLLocation = locations[0] as CLLocation

    manager.stopUpdatingLocation()

    let location = CLLocationCoordinate2D(latitude: userlocation.coordinate.latitude, longitude: userlocation.coordinate.longitude)

    let span = MKCoordinateSpanMake(0.5, 0.5)

    let region = MKCoordinateRegion(center: location, span: span)

    Mapview.setRegion(region, animated: true)

    let locationStrings = ["42.6977,23.3219","43.6977,24.3219"]

    // This array must be an array that contains CLLocation objects        
    var locations: [CLLocation] = []

    // We must retrieve the latitude and longitude from locationStrings array to convert them into CLLocation objects
    for locationString in locationStrings {

        let location = CLLocation(latitude: <latitude_value>, longitude: <latitude_value>)

        locations.append(location)

    }

    // Then you will be able to enumerate through the array
    for location in locations {

        let distanceMeters = userLocation.distanceFromLocation(location)

        if distanceMeters > 5000 { // Some distance filter
            // Don't display this location
        } else {
            // Display this location
        }

    }

Answer 2

您可以使用distanceFromLocation方法获取距离

let distance = userlocation.distanceFromLocation(YourPinInMap)

Answer 3

  locA = [[CLLocation alloc] initWithLatitude:[[[NSUserDefaults standardUserDefaults]valueForKey:@"startLat"]floatValue] longitude:[[[NSUserDefaults standardUserDefaults]valueForKey:@"startlong"]floatValue]];


 locB = [[CLLocation alloc] initWithLatitude:[[[NSUserDefaults standardUserDefaults]valueForKey:@"destLat"]floatValue]  longitude:[[[NSUserDefaults standardUserDefaults]valueForKey:@"destLong"]floatValue]];


distance = [locA distanceFromLocation:locB];

where locA and locB are CLLocation type pass the lat long over there