MapView not displaying Route - swift

Question

I have already checked that coordinates are available, but when I launch the map snaps to Antartica, and the route is not drawn when I go to the place in the map it should be.
I am attempting to do this programatically so maybe there is something I missed, if you spot it please let me know. There is no additional code
import UIKit
import MapKit
class ViewController: UIViewController {
var locationManager : CLLocationManager?
var routeData : Route?
var routeCoordinates : [CLLocation] = []
var routeOverlay: MKOverlay?
let mapView : MKMapView = {
let map = MKMapView()
map.overrideUserInterfaceStyle = .dark
map.translatesAutoresizingMaskIntoConstraints = false
return map
}()
override func viewWillAppear(_ animated: Bool) {
setMapConstraints()
}
override func viewDidLoad() {
super.viewDidLoad()
if let routeJSON = self.getJSON() {
self.parseJSON(jsonData: routeJSON)
}
drawRoute(routeData: routeCoordinates)
print(routeCoordinates)
}
private func setMapConstraints() {
view.addSubview(mapView)
mapView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
mapView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
mapView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
mapView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
}
//Omitted - functions for parsing local JSON file - tested and is working fine
//Function that handles drawing of route on map
func drawRoute(routeData: [CLLocation]) {
if routeCoordinates.count == 0 {
return
}
let coordinates = routeCoordinates.map { (location) -> CLLocationCoordinate2D in
return location.coordinate
}
DispatchQueue.main.async {
self.routeOverlay = MKPolyline(coordinates: coordinates, count: coordinates.count)
self.mapView.addOverlay(self.routeOverlay!, level: .aboveRoads)
let customEdgePadding: UIEdgeInsets = UIEdgeInsets(top: 40, left: 20, bottom: 40, right: 20)
self.mapView.setVisibleMapRect(self.routeOverlay!.boundingMapRect, edgePadding: customEdgePadding, animated: false)
}
}
}
extension ViewController : MKMapViewDelegate {
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
let renderer = MKPolylineRenderer(overlay: overlay)
renderer.strokeColor = .systemIndigo
renderer.lineCap = .round
renderer.lineWidth = 3.0
return renderer
}
}