Draw polyline using Swift

Question

I\'m trying to get an understanding of how to draw polylines using Swift. I\'ve looked at the documentation, referenced some tutorials, and checked out some other SO posts,

Answer 1

Here MKGeodesicPolyline will solve your problem. Add object of MKGeodesicPolyline instead of MKPolyline.

In your code remove below two lines:

    let polyline = MKPolyline(coordinates: &coordinates, count: locations.count)
    map.add(polyline)

And add these lines:

    let geodesic = MKGeodesicPolyline(coordinates: coordinates, count: 2)
    map.addOverlay(geodesic)

Swift 5.0:

func createPolyline(mapView: MKMapView) {
    let point1 = CLLocationCoordinate2DMake(-73.761105, 41.017791);
    let point2 = CLLocationCoordinate2DMake(-73.760701, 41.019348);
    let point3 = CLLocationCoordinate2DMake(-73.757201, 41.019267);
    let point4 = CLLocationCoordinate2DMake(-73.757482, 41.016375);
    let point5 = CLLocationCoordinate2DMake(-73.761105, 41.017791);
    
    let points: [CLLocationCoordinate2D]
    points = [point1, point2, point3, point4, point5]
    
    let geodesic = MKGeodesicPolyline(coordinates: points, count: 5)
    map.addOverlay(geodesic)
    
    UIView.animate(withDuration: 1.5, animations: { () -> Void in
        let span = MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01)
        let region1 = MKCoordinateRegion(center: point1, span: span)
        self.map.setRegion(region1, animated: true)
    })
}

Objective C code:

- (void) createGeoPolyline {
    
    CLLocationCoordinate2D point1 = { -73.761105, 41.017791 };
    CLLocationCoordinate2D point2 = { -73.760701, 41.019348 };
    CLLocationCoordinate2D point3 = { -73.757201, 41.019267 };
    CLLocationCoordinate2D point4 = { -73.757482, 41.016375 };
    CLLocationCoordinate2D point5 = { -73.761105, 41.017791 };

   CLLocationCoordinate2D points[] = {point1, point2, point3, point4, point5};
    
    MKGeodesicPolyline *geodesic = [MKGeodesicPolyline polylineWithCoordinates:&points[0] count:5];
    [self.mapView addOverlay:geodesic];
    
    [UIView animateWithDuration:1.5 animations:^{
        MKCoordinateRegion region;
        region.center = point1;
        
        MKCoordinateSpan span;
        span.latitudeDelta  = 0.01;
        span.longitudeDelta = 0.01;
        region.span = span;
        [self.mapView setRegion:region animated:YES];
    }];
}

Above Objective C code works perfect and it will show overlay below:

But if you try Swift code it will not. I tried as much as I can to solve it out but It won't change. May be it is bug from MapKit framework.