Route generation
The routes used in the Navigation SDK are generated by the Mapbox Directions API. When you install the Navigation SDK, it provides a convenient way to access the Mapbox Directions API in iOS applications.
To generate a route, you'll create a new NavigationRoutes struct. In most cases, you'll also use the NavigationRouteOptions class to set a few options.
RoutingProvider is the main protocol responsible for generating routes. It's implemented by the MapboxRoutingProvider class, which is part of the Mapbox Navigation SDK. It has two main methods:
- Calculate routes using Mapbox Directions API:
calculateRoutes(options:) - Calculate routes using Mapbox Map Matching API
calculateRoutes(options:)method.
An instance of MapboxRoutingProvider can be obtained from MapboxNavigation which is itself obtained from MapboxNavigationProvider. MapboxNavigationProvider is the main entrypoint of the Mapbox Navigation SDK and you have to create it yourself. Usually the route generation process looks like this:
let mapboxNavigationProvider = MapboxNavigationProvider(coreConfig: .init())
let mapboxNavigation = navigationProvider.mapboxNavigation
let routingProvider = mapboxNavigation.routingProvider()
let routes = try await routingProvider.calculateRoutes(options: routeOptions).value
Below are examples of how you can use specific options to generate routes for a few scenarios.
Request a route in a specific direction
With the Navigation SDK, you can consider the direction a user’s device is facing and request a route starting in a specific direction. To receive a route in a specific direction (for example, the direction a user is traveling or the direction a device is facing), pass in the user’s location heading value. This property corresponds to the angles in the bearings query parameter in the Mapbox Directions and Map Matching APIs.
Waypoint: In the adjacent diagram, the blue dot with white stroke is the device location. Imagine this is the first (origin) Waypoint in a Directions API request.
Heading: The Waypoint.heading can be used to influence the direction in which a route leg should begin. The heading value is the angle clockwise from true north between 0 and 359. For example, when the heading value is 0, the heading direction is due north. In the adjacent diagram, the pink arrow is the direction that the device is the heading (which is due west or 270°).
Heading accuracy: The Waypoint.headingAccuracy is the range of degrees by which a route can deviate from the Waypoint.heading angle and still be recommended. The semi-transparent blue area illustrates headingAccuracy. In this example headingAccuracy is 90° (45° in either direction from the heading angle).
The system sets the default value for heading to −1°, meaning it will not take the heading into account when calculating a route.
Consider the direction a user is already traveling
If you need to request a route that's continuing along the path that the user is traveling, set the Waypoint.heading to use CLLocation.course. This may be appropriate for driving directions. Consider that the phone may be in a center cup holder, facing the driver rather than the rear-view mirror, as the car moves in a forward direction. You can also set a custom Waypoint.headingAccuracy.
This can be applied to any waypoint including the origin, stops along the route, and the destination.
let mapboxNavigation = navigationProvider.mapboxNavigation
guard let location = mapboxNavigation.navigation().currentLocationMatching?.location else { return }
var userWaypoint = Waypoint(location: location)
userWaypoint.heading = location.course
userWaypoint.headingAccuracy = 90.0
Specify a side of the road to approach
By default, routes generated will approach waypoints on either side of road. You can override the default by setting Waypoint.allowsArrivingOnOppositeSide to false. This will require that the route has the driver approach the waypoint on the same side of the road the waypoint is on. allowsArrivingOnOppositeSide corresponds to the approaches query parameter in the Mapbox Directions and Map Matching APIs.
let location: CLLocation = ...
var userWaypoint = Waypoint(location: location)
userWaypoint.allowsArrivingOnOppositeSide = false
Include multiple stops
The Mapbox Directions API requires at least two waypoints to generate a route. If your route involves several pick-up and drop-off points, you can add up to 25 coordinates (including the origin and destination) using the automobile profile or three coordinates using the automobileAvoidingTraffic profile. These coordinates are treated as stops between the origin and destination in the order that you add them — the first waypoint is the origin and the second waypoint is the first stop:
let routeOptions = NavigationRouteOptions(waypoints: [
Waypoint(coordinate: CLLocationCoordinate2D(latitude: 37.77766, longitude: -122.43199)),
Waypoint(coordinate: CLLocationCoordinate2D(latitude: 37.77609, longitude: -122.43292)),
Waypoint(coordinate: CLLocationCoordinate2D(latitude: 37.77536, longitude: -122.43494)),
])
let core = navigationProvider.mapboxNavigation
let routingProvider = core.routingProvider()
let routes = try await routingProvider.calculateRoutes(options: routeOptions).value
Silent waypoints
The Waypoint.separatesLegs property determines if a waypoint will be treated as a stop between legs or only influence the route without mentioning it in maneuver instructions.
By default Waypoint.separatesLegs is equal to true meaning the waypoint will appear in the resulting routes as a waypoint separating two legs, along with corresponding guidance instructions.
If you want to make sure that the route you request passes through the waypoint without specifically mentioning it, set Waypoint.separatesLegs equal to false.
Optimized routes
If you want to generate a route that will arrive at the waypoints in the fastest order (not necessarily in a specific order), see the Optimization API documentation.
Route generation in offline mode
Default implementation of protocol RoutingProvider named MapboxRoutingProvider automatically generates routes using the onboard routing engine when the device is offline, providing enough cached tiles are available.