Route Profile
In this guide you will learn how to display a map, calculate routes between multiple points, and show a detailed route profile.
How it Works
This example demonstrates the following key features:
- Calculates routes and renders them on the map.
- Display detailed route profile, including an elevation chart that visualizes the terrain along the route.
Elevation chart
Detailed route profile
UI and Map Integration
The following code demonstrates how to create a UI with a GemMap and an app bar featuring a "Build Route" button. After the route is calculated, a scrollable route profile panel appears at the bottom of the screen, along with a close button in the top-right corner of the app bar.
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(debugShowCheckedModeBanner: false, title: 'Route Profile', home: MyHomePage());
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
late GemMapController _mapController;
// We use the handler to cancel the route calculation.
TaskHandler? _routingHandler;
Route? _focusedRoute;
final LineAreaChartController _chartController = LineAreaChartController();
@override
void dispose() {
GemKit.release();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.deepPurple[900],
title: const Text('Route Profile', style: TextStyle(color: Colors.white)),
actions: [
// Routes are not built.
if (_routingHandler == null && _focusedRoute == null)
IconButton(
onPressed: () => _onBuildRouteButtonPressed(context),
icon: const Icon(Icons.route, color: Colors.white),
),
// Routes calculating is in progress.
if (_routingHandler != null)
IconButton(
onPressed: () => _onCancelRouteButtonPressed(),
icon: const Icon(Icons.stop, color: Colors.white),
),
// Routes calculating is finished.
if (_focusedRoute != null)
IconButton(
onPressed: () => _onClearRoutesButtonPressed(),
icon: const Icon(Icons.clear, color: Colors.white),
),
],
),
body: Stack(
children: [
GemMap(key: ValueKey("GemMap"), onMapCreated: _onMapCreated, appAuthorization: projectApiToken),
if (_focusedRoute != null)
Align(
alignment: Alignment.bottomCenter,
child: RouteProfilePanel(
route: _focusedRoute!,
mapController: _mapController,
chartController: _chartController,
centerOnRoute: () => _centerOnRoute([_focusedRoute!]),
),
),
],
),
);
}
// The callback for when map is ready to use.
Future<void> _onMapCreated(GemMapController controller) async {
// Save controller for further usage.
_mapController = controller;
// Register route tap gesture callback.
await _registerRouteTapCallback();
}
void _onBuildRouteButtonPressed(BuildContext context) {
// Define the departure.
final departureLandmark = Landmark.withLatLng(latitude: 46.59344, longitude: 7.91069);
// Define the destination.
final destinationLandmark = Landmark.withLatLng(latitude: 46.55945, longitude: 7.89293);
// Define the route preferences.
// Terrain profile has to be enabled for this example to work.
final routePreferences = RoutePreferences(
buildTerrainProfile: const BuildTerrainProfile(enable: true),
transportMode: RouteTransportMode.pedestrian,
);
_showSnackBar(context, message: "The route is being calculated.");
// Calling the calculateRoute SDK method.
// (err, results) - is a callback function that gets called when the route computing is finished.
// err is an error enum, results is a list of routes.
_routingHandler = RoutingService.calculateRoute([departureLandmark, destinationLandmark], routePreferences, (
err,
routes,
) {
// If the route calculation is finished, we don't have a progress listener anymore.
_routingHandler = null;
ScaffoldMessenger.of(context).clearSnackBars();
// If there aren't any errors, we display the routes.
if (err == GemError.success) {
// Get the routes collection from map preferences.
final routesMap = _mapController.preferences.routes;
// Display the routes on map.
for (final route in routes) {
routesMap.add(route, route == routes.first, label: getMapLabel(route));
}
// Center the camera on routes.
_centerOnRoute(routes);
setState(() {
_focusedRoute = routes.first;
});
}
});
setState(() {});
}
void _onClearRoutesButtonPressed() {
_mapController.preferences.paths.clear();
// Remove the routes from map.
_mapController.preferences.routes.clear();
setState(() {
_focusedRoute = null;
});
}
void _onCancelRouteButtonPressed() {
// If we have a progress listener we cancel the route calculation.
if (_routingHandler != null) {
RoutingService.cancelRoute(_routingHandler!);
setState(() {
_routingHandler = null;
});
}
}
// In order to be able to select an alternative route, we have to register the route tap gesture callback.
Future<void> _registerRouteTapCallback() async {
// Register the generic map touch gesture.
_mapController.registerTouchCallback((pos) async {
// Select the map objects at gives position.
await _mapController.setCursorScreenPosition(pos);
// Get the selected routes.
final routes = _mapController.cursorSelectionRoutes();
// If there is a route at position, we select it as the main one on the map.
if (routes.isNotEmpty) {
_mapController.preferences.routes.mainRoute = routes.first;
// Reset the highlight on the chart.
if (_chartController.setCurrentHighlight != null) {
_chartController.setCurrentHighlight!(0);
}
setState(() {
_focusedRoute = routes.first;
});
// Center the camera on the main route.
_centerOnRoute([_focusedRoute!]);
}
});
}
void _centerOnRoute(List<Route> route) {
const appbarHeight = 50;
const padding = 20;
// Use the map controller to center on route above the panel.
_mapController.centerOnRoutes(
routes: route,
screenRect: RectType(
x: 0,
y: (appbarHeight + padding * MediaQuery.of(context).devicePixelRatio).toInt(),
width: (MediaQuery.of(context).size.width * MediaQuery.of(context).devicePixelRatio).toInt(),
height:
((MediaQuery.of(context).size.height / 2 -
appbarHeight -
2 * padding * MediaQuery.of(context).devicePixelRatio) *
MediaQuery.of(context).devicePixelRatio)
.toInt(),
),
);
}
Displaying Route Information
// Show a snackbar indicating that the route calculation is in progress.
void _showSnackBar(BuildContext context, {required String message, Duration duration = const Duration(hours: 1)}) {
final snackBar = SnackBar(content: Text(message), duration: duration);
ScaffoldMessenger.of(context).showSnackBar(snackBar);
}
}
String getMapLabel(Route route) {
return '${convertDistance(route.getTimeDistance().totalDistanceM)} \n${convertDuration(route.getTimeDistance().totalTimeS)}';
}
// Utility function to convert the meters distance into a suitable format.
String convertDistance(int meters) {
if (meters >= 1000) {
double kilometers = meters / 1000;
return '${kilometers.toStringAsFixed(1)} km';
} else {
return '${meters.toString()} m';
}
}
// Utility function to convert the seconds duration into a suitable format.
String convertDuration(int seconds) {
int hours = seconds ~/ 3600; // Number of whole hours
int minutes = (seconds % 3600) ~/ 60; // Number of whole minutes
String hoursText = (hours > 0) ? '$hours h ' : ''; // Hours text
String minutesText = '$minutes min'; // Minutes text
return hoursText + minutesText;
}