title: How to add overlay path in MKMapView swift
body: <p>I want to add a overlay path among multiple coordinates in mapview. I tried like below code, but it shows a error of "cannot invoke 'map' with an argument list of type ((CLLocation) -> CLLocationCoordinate2D)". Please let me know how can i fix this ?</p>
  
  <p>My ViewController.swift file</p>
  
  <pre><code>import UIKit
  import MapKit
  
  class ViewController: UIViewController, MKMapViewDelegate{
      @IBOutlet weak var mapView: MKMapView!
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          //For Location 1
          let location1 = CLLocationCoordinate2D(
              latitude: 51.481188400000010000,
              longitude: -0.190209099999947280
          )
  
          let annotation1 = MKPointAnnotation()
          annotation1.coordinate = location1;
          annotation1.title = "Chelsea"
          annotation1.subtitle = "Chelsea"
  
          let span = MKCoordinateSpanMake(0.15, 0.15)
  
          let region1 = MKCoordinateRegion(center: location1, span: span)
          mapView.setRegion(region1, animated: true)
          mapView.addAnnotation(annotation1)
  
          //For Location 2
          let location2 = CLLocationCoordinate2D(
              latitude: 51.554947700000010000,
              longitude: -0.108558899999934510
          )
  
          let annotation2 = MKPointAnnotation()
          annotation2.coordinate = location2;
          annotation2.title = "Arsenal"
          annotation2.subtitle = "Arsenal"
  
          let region2 = MKCoordinateRegion(center: location1, span: span)
          mapView.setRegion(region2, animated: true)
          mapView.addAnnotation(annotation2)
  
          var locations = [CLLocation(latitude: 51.481188400000010000, longitude: -0.190209099999947280), CLLocation(latitude: 51.554947700000010000,longitude:  -0.108558899999934510)]
  
          //This line shows error
          var coordinates = locations.map({(location: CLLocation) -&gt; CLLocationCoordinate2D in return location.coordinate})
  
          var polyline = MKPolyline(coordinates: &amp;coordinates, count: locations.count)
  
          mapView.addOverlay(polyline)
      }
  
      func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -&gt; MKOverlayRenderer! {
          if overlay is MKPolyline {
              var polylineRenderer = MKPolylineRenderer(overlay: overlay)
              polylineRenderer.strokeColor = UIColor.blueColor()
              polylineRenderer.lineWidth = 5
              return polylineRenderer
          }
  
          return nil
      }
  
      override func didReceiveMemoryWarning() {
          super.didReceiveMemoryWarning()
          // Dispose of any resources that can be recreated.
      }
  }
  </code></pre>