Adding a route to a MKMapView

Question

I'm trying to add a routing feature to an app I'm working on. I found Craig Spitzkoff's article on how to draw lines on an MKMapView which works pretty good. But since I don't have the coordinates of the points on the roads that doesn't help me as expected. Is there any way to determine the coordinates between to given points, say my current position and another address?

Answer 1

Basically you will need to make an HTTP request to the Google Directions API. The terms of service state that you have to display the results on a Google map, but I think because you are using an MKMapView, you will be fine:

the Directions API may only be used in conjunction with displaying results on a Google map; using Directions data without displaying a map for which directions data was requested is prohibited.

Check out the Directions Request for details on the parameters you will need to pass on the URL:

http://maps.google.com/maps/api/directions/output?parameters

The data you get back will be JSON or XML depending on what you asked for (output), so you will need to parse that to get the set of points describing the directions.

Answer 2

I know this is an old question, but nowadays you can also use MapKit’s MKDirections. For example, here’s a routine to search for some searchString and then add directions to the first hit on to your map view:

let request = MKLocalSearch.Request()
request.region = mapView.region
request.naturalLanguageQuery = searchString

let search = MKLocalSearch(request: request)
search.start { response, _ in
    guard let mapItem = response?.mapItems.first else { return }

    let request = MKDirections.Request()
    request.source = MKMapItem.forCurrentLocation()
    request.destination = mapItem
    let directions = MKDirections(request: request)
    directions.calculate { response, error in
        guard let routes = response?.routes else { return }

        let overlays = routes.map { $0.polyline }
        self.mapView.addOverlays(overlays)
    }
}

To make sure this is rendered on your map, you would make sure to set your map view’s delegate property (either in IB or programmatically) and then implement mapView(_:rendererFor:):

extension MapViewController: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let renderer = MKPolylineRenderer(overlay: overlay)
        renderer.strokeColor = .init(red: 0, green: 0, blue: 1, alpha: 0.7)
        return renderer
    }
}