Navigation

SDK allows you to implement the following navigation scenarios:

• Start the navigator in various modes (free-drive, turn-by-turn, and simulated navigation), including indoor navigation mode.
• Suggest alternative routes to a user along the way.
• Get dynamic route data during navigation.

You can add a turn-by-turn navigation to your app using the ready-to-use interface components and a NavigationManager object:

import 'package:dgis_mobile_sdk_full/dgis.dart' as sdk;

final sdk.Context sdkContext = sdk.DGis.initialize();
final sdk.NavigationManager navigationManager = sdk.NavigationManager(sdkContext);

Add a location marker to the map and connect the map with a NavigationManager object.

import 'package:dgis_mobile_sdk_full/dgis.dart' as sdk;

final sdk.MyLocationMapObjectSource locationSource = sdk.MyLocationMapObjectSource(sdkContext);
map.addSource(locationSource);

navigationManager.mapManager.addMap(map);

You can start navigation in one of the three modes: free-drive, turn-by-turn, or simulated navigation.

Additional navigation settings can be changed using the properties of a NavigationManager object.

Free-drive mode

In free-drive mode, no route will be displayed on the map, but the user will still be informed about speed limits, traffic cameras, incidents, and road closures.

To start navigation in this mode, call the startFreeRoam() method without parameters.

import 'package:dgis_mobile_sdk_full/dgis.dart' as sdk;

final sdk.Context sdkContext = sdk.DGis.initialize();
final sdk.NavigationManager navigationManager = sdk.NavigationManager(sdkContext);

navigationManager.startFreeRoam();

Turn-by-turn mode

In turn-by-turn mode, a route will be displayed on the map, and the user will receive navigation instructions as they move along the route.

To start navigation in this mode, call the start() method and specify a RouteBuildOptions object – arrival coordinates and route settings.

import 'package:dgis_mobile_sdk_full/dgis.dart' as sdk;

final routeBuildOptions = sdk.RouteBuildOptions(
    finishPoint: sdk.RouteSearchPoint(
        coordinates: sdk.GeoPoint(
            latitude: sdk.Latitude(55.757670),
            longitude: sdk.Longitude(37.660160),
        ),
    ),
    routeSearchOptions: sdk.RouteSearchOptions.car(
        sdk.CarRouteSearchOptions(),
    ),
);

navigationManager.start(routeBuildOptions);

Additionally, when calling the start() method, you can specify a TrafficRoute object – a complete route object for navigation (for details, see the Routing chapter). In this case, a NavigationManager object will use the specified route instead of building a new one.

navigationManager.start(routeBuildOptions, trafficRoute);

Simulated navigation

In this mode, a NavigationManager object will not track the current location of the device. Instead, it will simulate a movement along the specified route. This mode is useful for debugging.

To use this mode, call the startSimulation() method and specify a RouteBuildOptions object (the route settings) and a TrafficRoute object (the route itself).

You can change the speed of the simulated movement using the SimulationSettings.speedMode property (specified in meters per second).

navigationManager.simulationSettings.speedMode = sdk.SimulationSpeedMode.overSpeed(
  sdk.SimulationAutoWithOverSpeed(10)
);

navigationManager.startSimulation(routeBuildOptions, trafficRoute);

To stop the simulation, call the stop() method:

navigationManager.stop();

Indoor navigation

  

The SDK provides the ability to build routes within certain buildings for which there are floor plans. For example, you can build a route to a specific store in a mall, make a complex route between several points, etc.

This type of navigation is included in the Full SDK, but has a number of limitations:

• Can only be activated in pedestrian navigation mode.
• Due to the way modern positioning systems work, the ability to determine the position inside buildings is severely limited. When the system determines that the device has entered the limits of the building, the geopositioning tracking and its display will be disabled, leaving only the constructed route and recommendations for the passage.

Creating a route

Creating a route follows the principles described in Turn-by-turn mode with a few important additions. When creating a route endpoint RouteSearchPoint, the objectId and levelId parameters are mandatory.

import 'package:dgis_mobile_sdk_full/dgis.dart' as sdk;

// RouteBuildOptions object is also required
final routeBuildOptions = sdk.RouteBuildOptions(
    finishPoint: sdk.RouteSearchPoint(
        coordinates: sdk.GeoPoint(
            latitude: sdk.Latitude(55.757670),
            longitude: sdk.Longitude(37.660160),
        ),
        objectId: ..., // You can get it from DgisMapObject
        levelId: ..., // You can get it from DirectoryObject or RenderedObjectInfo
    ),
    // The type of routeSearchOptions is PedestrianRouteSearchOptions
    routeSearchOptions: sdk.RouteSearchOptions.pedestrian(
        sdk.PedestrianRouteSearchOptions(),
    ),
);

Displaying a route

You can use the standard SDK features to detect when a user enters the indoor navigation mode by subscribing to an indoorChannel channel. This channel can be obtained from NavigationManager.indoorDetector.

Alternative routes

While driving along a car route, the navigator regularly searches for other ways to reach the destination point. For alternative routes search, all specified route parameters and intermediate points (except for already visited ones) are taken into account.

An alternative route is displayed on the map when a corresponding intersection is approaching, but the user still has enough time to make a decision.

The alternative route is shown on the map as a line with a bubble indicating the difference in travel time: how much time the user saves or loses if they switch to the alternative route. To switch to this route, the user can tap the route line on the screen or simply turn onto the alternative route at the intersection. If the user continues driving along the main route at the intersection, the alternative route disappears from the map.

"Better Route"

Among the alternative routes, a special type called the "better route" may be highlighted if a route meets the following criteria:

• The expected travel duration on the "better route" must be significantly shorter than the remaining part of the main route. The default difference is 5 minutes.
• The "better route" must be significantly different from the main route in geometry (in the roads it passes). By default, the difference in the length of differing route segments is 500 meters.

If a "better route" is found among the detected alternative routes, an additional UI control is displayed on the map. By tapping this element, the user can either switch to the "better route" or explicitly decline it. This element disappears from the screen after a certain time (30 seconds by default), but the route line continues to be displayed on the map until the user passes the intersection.

At any given time, only one route can be suggested to the user as the "better route". The search for a new "better route" begins after the user explicitly declines the previous one (by tapping the UI control) or after passing the intersection where the "better route" was available.

Parameters of alternative routes search

To change the parameters for searching for alternative routes, use the AlternativeRoutesProviderSettingsproperty of the NavigationManager object:

navigationManager.alternativeRoutesProviderSettings.alternativeRoutesEnabled = true;

To switch navigation to an alternative route, use AlternativeRouteSelector:

navigationManager.alternativeRouteSelector.selectAlternativeRoute(route);

Dynamic route information

During navigation, you can receive dynamic route information through the uiModel property in NavigationManager and display it in the navigator UI. The Model class provides the following parameters:

• navigator state (state and stateChannel)
• current geolocation used by the navigator (location and locationChannel)
• flag indicating if current geolocation is being used for navigation (locationAvailable and locationAvailableChannel)
• route information with maneuvers (route and routeChannel)
• road events and traffic data on the route (dynamicRouteInfo and dynamicRouteInfoChannel)
• current user position on the route (routePosition and routePositionChannel)
• flag indicating if the speed limit is exceeded (exceedingMaxSpeedLimit and exceedingMaxSpeedLimitChannel)
• flag indicating if a "better route" is found (betterRoute and betterRouteChannel)
• distance (distance) and time (duration) to the end of the route
• flag indicating if the free roam mode is used (isFreeRoam)

The route information in Model changes dynamically relative to the user current position on the route. To get the current position, subscribe to the routePositionChannel and then use this value to obtain other route data. See more about working with channels in the Data channels section.

For example, you can get the following information:

• Distance (distance) and time (duration) from the current point to the end of the route:

  // Channel for getting a position on the route
  final positionChannel = navigationManager.uiModel.routePositionChannel;
  
  final subscription = positionChannel.listen((routePosition) {
  WidgetsBinding.instance.addPostFrameCallback((_) {
  
      // Distance to the end of the route in meters
      final distance = navigationManager.uiModel.distance();
  
      // Time to the end of the route in seconds
      final duration = navigationManager.uiModel.duration();
  
      ...
      });
  });
  

• Road events and traffic jam data (dynamicRouteInfo). Road events data is stored in the RoadEventRouteAttribute and you can get an element from it by a position on the route.

  For example, to get the next nearest road event on the route:

  // Channel for getting a position on the route
  final positionChannel = navigationManager.uiModel.routePositionChannel;
  
  final subscription = positionChannel.listen((routePosition) {
  WidgetsBinding.instance.addPostFrameCallback((_) {
  
      // Get the nearest road event relative to the current position
      final dynamicInfo = navigationManager.uiModel.dynamicRouteInfo;
      final nearestEvent = dynamicInfo.roadEvents?.findNearForward(routePosition);
  
      ...
      });
  });
  

• Current navigator state. You can get it by subscribing to the stateChannel channel or separately (state):

  // Get navigator state outside of the channel
  final currentState = navigationManager.uiModel.state;
  

  // Channel for getting navigator state
  final stateChannel = navigationManager.uiModel.stateChannel;
  
  final subscription = stateChannel.listen((state) {
  WidgetsBinding.instance.addPostFrameCallback((_) {
      ...
      });
  });
  

  Navigator can be in one of the following states:

  • disabled - inactive (initial state).
  • navigation - in the turn-by-turn navigation mode.
  • routeSearch - searching for a new route.
  • finished - completed navigation on the route (the finish point is reached).