How do i remove this default red marker from google maps iOS Swift - ios

Question

I want to remove this red pins. I am adding custom pins to source (yellow pin) and destination (blue pin, but I still not understand why this red pins also show ?
Here is Code :-
func reDrawRoute(pickupCoordinate : CLLocationCoordinate2D, destinationCoordinate :CLLocationCoordinate2D, type: String) {
// func setMapMarkersRoute(vLoc: CLLocationCoordinate2D, toLoc: CLLocationCoordinate2D) {
self.sourceMarker.map = nil
self.destMarker.map = nil
//add the markers for the 2 locations
if type == "S2D" {
self.sourceMarker = GMSMarker.init(position: pickupCoordinate)
self.sourceMarker.icon = UIImage(named: "source")
self.sourceMarker.map = gMapView
self.destMarker = GMSMarker.init(position: destinationCoordinate)
self.destMarker.icon = UIImage(named: "destination")
self.destMarker.map = gMapView
} else if type == "C2S" {
self.carMarker.position = pickupCoordinate
self.carMarker.icon = UIImage(named: "pin-car")
self.carMarker.map = gMapView
self.destMarker = GMSMarker.init(position: destinationCoordinate)
self.destMarker.icon = UIImage(named: "source")
self.destMarker.map = gMapView
} else if type == "C2D" {
self.carMarker.position = pickupCoordinate
self.carMarker.icon = UIImage(named: "pin-car")
self.carMarker.map = gMapView
self.destMarker = GMSMarker.init(position: destinationCoordinate)
self.destMarker.icon = UIImage(named: "destination")
self.destMarker.map = gMapView
}
//zoom the map to show the desired area
var bounds = GMSCoordinateBounds()
bounds = bounds.includingCoordinate(pickupCoordinate)
bounds = bounds.includingCoordinate(destinationCoordinate)
self.gMapView.moveCamera(GMSCameraUpdate.fit(bounds))
//finally get the route
getRoute(from: pickupCoordinate, to: destinationCoordinate)
}
This is for getting route coordinates between source and destination.
func getRoute(from: CLLocationCoordinate2D, to: CLLocationCoordinate2D) {
let source = MKMapItem(placemark: MKPlacemark(coordinate: from))
let destination = MKMapItem(placemark: MKPlacemark(coordinate: to))
let request = MKDirections.Request()
request.source = source
request.destination = destination
request.requestsAlternateRoutes = false
let directions = MKDirections(request: request)
directions.calculate(completionHandler: { (response, error) in
if let res = response {
//the function to convert the result and show
self.show(polyline: self.googlePolylines(from: res))
}
})
}
This code is for showing route.
private func googlePolylines(from response: MKDirections.Response) -> GMSPolyline {
let route = response.routes[0]
var coordinates = [CLLocationCoordinate2D](
repeating: kCLLocationCoordinate2DInvalid,
count: route.polyline.pointCount)
route.polyline.getCoordinates(
&coordinates,
range: NSRange(location: 0, length: route.polyline.pointCount))
let polyline = Polyline(coordinates: coordinates)
let encodedPolyline: String = polyline.encodedPolyline
let path = GMSPath(fromEncodedPath: encodedPolyline)
return GMSPolyline(path: path)
}
I am using this method for adding custom markers..