Offline routing

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Solve a route on-the-fly using offline data.

Image of offline routing

Use case

You can use an offline network to enable routing in disconnected scenarios. For example, you could provide offline location capabilities to field workers repairing critical infrastructure in a disaster when network availability is limited.

How to use the sample

Tap near a road to start adding a stop to the route, tap again to place it on the map. A number graphic will show its order in the route. After adding at least 2 stops, a route will display. Choose "Fastest" or "Shortest" to control how the route is optimized. The route will update on-the-fly while moving stops. The green box marks the boundary of the routable area provided by the offline data. This sample limits routes to 5 stops for performance reasons.

How it works

Create the map's Basemap from a local tile package using a TileCache and ArcGISTiledLayer
Create a RouteTask with an offline locator geodatabase.
Get the RouteParameters using routeTask.CreateDefaultParameters()
Create Stops and add them to the route task's parameters.
Solve the Route using routeTask.SolveRouteAsync(routeParameters)
Create a graphic with the route's geometry and a SimpleLineSymbol and display it on another GraphicsOverlay.

Relevant API

RouteParameters
RouteResult
RouteTask
Stop
TravelMode

Offline data

The data used by this sample is available on ArcGIS Online.

About the data

This sample uses a pre-packaged sample dataset consisting of a geodatabase with a San Diego road network and a tile package with a streets basemap.

Sample Code

OfflineRouting.xaml.cs

OfflineRouting.xaml

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﻿// Copyright 2022 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using ArcGIS.Samples.Managers;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks.NetworkAnalysis;
using Esri.ArcGISRuntime.UI;
using System.Reflection;

using Color = System.Drawing.Color;

namespace ArcGIS.Samples.OfflineRouting
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Offline routing",
        category: "Network analysis",
        description: "Solve a route on-the-fly using offline data.",
        instructions: "Tap near a road to start adding a stop to the route, tap again to place it on the map. A number graphic will show its order in the route. After adding at least 2 stops, a route will display. Choose \"Fastest\" or \"Shortest\" to control how the route is optimized. The route will update on-the-fly while moving stops. The green box marks the boundary of the routable area provided by the offline data. This sample limits routes to 5 stops for performance reasons.",
        tags: new[] { "connectivity", "disconnected", "fastest", "locator", "navigation", "network analysis", "offline", "routing", "shortest", "turn-by-turn" })]
    [ArcGIS.Samples.Shared.Attributes.OfflineData("567e14f3420d40c5a206e5c0284cf8fc")]
    public partial class OfflineRouting : ContentPage
    {
        // Graphics overlays for holding graphics.
        private GraphicsOverlay _stopsOverlay;
        private GraphicsOverlay _routeOverlay;

        // Route task and parameters.
        private RouteTask _offlineRouteTask;
        private RouteParameters _offlineRouteParameters;

        // List of travel modes, like 'Fastest' and 'Shortest'.
        private List<TravelMode> _availableTravelModes;

        // The area covered by the geodatabase used for offline routing.
        private readonly Envelope _routableArea = new Envelope(new MapPoint(-13045352.223196, 3864910.900750, 0, SpatialReferences.WebMercator),
            new MapPoint(-13024588.857198, 3838880.505604, 0, SpatialReferences.WebMercator));

        public OfflineRouting()
        {
            InitializeComponent();
            _ = Initialize();
        }

        private async Task Initialize()
        {
            try
            {
                // Get the paths to resources used by the sample.
                string basemapTilePath = DataManager.GetDataFolder("567e14f3420d40c5a206e5c0284cf8fc", "streetmap_SD.tpkx");
                string networkGeodatabasePath = DataManager.GetDataFolder("567e14f3420d40c5a206e5c0284cf8fc", "sandiego.geodatabase");

                // Create the tile cache representing the offline basemap.
                TileCache tiledBasemapCache = new TileCache(basemapTilePath);

                // Create a tiled layer to display the offline tiles.
                ArcGISTiledLayer offlineTiledLayer = new ArcGISTiledLayer(tiledBasemapCache);

                // Create a basemap based on the tile layer.
                Basemap offlineBasemap = new Basemap(offlineTiledLayer);

                // Create a new map with the offline basemap.
                Map theMap = new Map(offlineBasemap);

                // Set the initial viewpoint to show the routable area.
                theMap.InitialViewpoint = new Viewpoint(_routableArea);

                // Show the map in the map view.
                MyMapView.Map = theMap;

                // Create overlays for displaying the stops and the calculated route.
                _stopsOverlay = new GraphicsOverlay();
                _routeOverlay = new GraphicsOverlay();

                // Create a symbol and renderer for symbolizing the calculated route.
                SimpleLineSymbol routeSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Blue, 2);
                _routeOverlay.Renderer = new SimpleRenderer(routeSymbol);

                // Add the stops and route overlays to the map.
                MyMapView.GraphicsOverlays.Add(_stopsOverlay);
                MyMapView.GraphicsOverlays.Add(_routeOverlay);

                // Create the route task, referring to the offline geodatabase with the street network.
                _offlineRouteTask = await RouteTask.CreateAsync(networkGeodatabasePath, "Streets_ND");

                // Get the list of available travel modes.
                _availableTravelModes = _offlineRouteTask.RouteTaskInfo.TravelModes.ToList();

                // Update the UI with the travel modes list.
                TravelModesCollection.ItemsSource = _availableTravelModes.ToList();
                TravelModesCollection.SelectedItem = _availableTravelModes.First();

                // Create the default parameters.
                _offlineRouteParameters = await _offlineRouteTask.CreateDefaultParametersAsync();

                // Display the extent of the road network on the map.
                DisplayBoundaryMarker();

                // Now that the sample is ready, hook up the tap event.
                MyMapView.GeoViewTapped += MapView_Tapped;
                TravelModesCollection.SelectionChanged += TravelModesCollection_SelectionChanged;
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.WriteLine(e);
                ShowMessage("Couldn't start sample", "There was a problem starting the sample. See debug output for details.");
            }
        }

        private void DisplayBoundaryMarker()
        {
            // Displaying the boundary marker helps avoid choosing a non-routable destination.
            SimpleLineSymbol boundarySymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Dash, Color.LawnGreen, 5);
            Graphic boundary = new Graphic(_routableArea, boundarySymbol);
            GraphicsOverlay boundaryOverlay = new GraphicsOverlay();
            boundaryOverlay.Graphics.Add(boundary);
            MyMapView.GraphicsOverlays.Add(boundaryOverlay);
        }

        private void ResetRoute()
        {
            _routeOverlay.Graphics.Clear();
            _stopsOverlay.Graphics.Clear();
        }

        private async Task UpdateRoute(TravelMode selectedTravelMode)
        {
            try
            {
                // Create a list of stops.
                List<Stop> stops = new List<Stop>();

                // Add a stop to the list for each graphic in the stops overlay.
                foreach (Graphic stopGraphic in _stopsOverlay.Graphics)
                {
                    Stop stop = new Stop((MapPoint)stopGraphic.Geometry);
                    stops.Add(stop);
                }

                if (stops.Count < 2)
                {
                    // Don't route, there's no where to go (and the route task would throw an exception).
                    return;
                }

                // Configure the route parameters with the list of stops.
                _offlineRouteParameters.SetStops(stops);

                // Configure the travel mode.
                _offlineRouteParameters.TravelMode = selectedTravelMode;

                // Solve the route.
                RouteResult offlineRouteResult = await _offlineRouteTask.SolveRouteAsync(_offlineRouteParameters);

                // Clear the old route result.
                _routeOverlay.Graphics.Clear();

                // Get the geometry from the route result.
                Polyline routeGeometry = offlineRouteResult.Routes.First().RouteGeometry;

                // Note: symbology left out here because the symbology was set once on the graphics overlay.
                Graphic routeGraphic = new Graphic(routeGeometry);

                // Display the route.
                _routeOverlay.Graphics.Add(routeGraphic);
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.WriteLine(e);
                ShowMessage("Couldn't update route", "There was an error updating the route. See debug output for details.");
            }
        }

        private async Task AddStop(Point tappedPosition)
        {
            try
            {
                // Get the location on the map.
                MapPoint tappedLocation = MyMapView.ScreenToLocation(tappedPosition);

                // Name the stop by its number.
                string stopName = $"{_stopsOverlay.Graphics.Count + 1}";

                // Create a pushpin marker for the stop.
                PictureMarkerSymbol pushpinMarker = await GetPictureMarker();

                // Create the text symbol for labeling the stop.
                TextSymbol stopSymbol = new TextSymbol(stopName, Color.White, 15,
                    Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Center, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Middle);
                stopSymbol.OffsetY = 15;

                // Create a combined symbol with the pushpin and the label.
                CompositeSymbol combinedSymbol = new CompositeSymbol(new MarkerSymbol[] { pushpinMarker, stopSymbol });

                // Create the graphic from the geometry and the symbology.
                Graphic newStopGraphic = new Graphic(tappedLocation, combinedSymbol);

                // Add the stop to the overlay.
                _stopsOverlay.Graphics.Add(newStopGraphic);
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.WriteLine(e);
                ShowMessage("Couldn't add stop", "Couldn't add stop. See debug output for details.");
            }
        }

        private async Task<PictureMarkerSymbol> GetPictureMarker()
        {
            // Get current assembly that contains the image.
            Assembly currentAssembly = Assembly.GetExecutingAssembly();

            // Get image as a stream from the resources.
            // Picture is defined as EmbeddedResource and DoNotCopy.
            Stream resourceStream = currentAssembly.GetManifestResourceStream(
                "ArcGIS.Resources.PictureMarkerSymbols.pin_blue.png");

            // Create new symbol using asynchronous factory method from stream.
            PictureMarkerSymbol pinSymbol = await PictureMarkerSymbol.CreateAsync(resourceStream);
            pinSymbol.Width = 50;
            pinSymbol.Height = 50;
            pinSymbol.LeaderOffsetX = 30;
            pinSymbol.OffsetY = 14;

            return pinSymbol;
        }

        private void ResetButton_Click(object sender, EventArgs e) => ResetRoute();

        private void MapView_Tapped(object sender, Esri.ArcGISRuntime.Maui.GeoViewInputEventArgs e)
        {
            // Make sure the user isn't adding too many stops.
            if (_stopsOverlay.Graphics.Count >= 5)
            {
                ShowMessage("Can't add stop.", "Sample limits to 5 stops per route.");
                return;
            }

            // Make sure the stop is valid before proceeding.
            if (!_routableArea.Contains(e.Location))
            {
                ShowMessage("Can't add stop.", "That location is outside of the area where offline routing data is available.");
                return;
            }

            // Add the stop for the tapped position.
            _ = AddStop(e.Position);

            // Update the route with the final list of stops.
            _ = UpdateRoute((TravelMode)TravelModesCollection.SelectedItem);
        }

        private void ShowMessage(string title, string detail)
        {
            Application.Current.MainPage.DisplayAlert(title, detail, "OK");
        }

        private void TravelModesCollection_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            try
            {
                // Enforce selection to prevent errors.
                if (TravelModesCollection.SelectedItem == null)
                {
                    TravelModesCollection.SelectedItem = _availableTravelModes.First();
                }

                // Update the route.
                _ = UpdateRoute((TravelMode)TravelModesCollection.SelectedItem);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
                ShowMessage("Couldn't change travel mode", "Couldn't change travel mode. See debug output for details.");
            }
        }
    }
}