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Create a notification every time a given location data source has entered and/or exited a set of features or graphics.

Image of Set up location-driven Geotriggers

Use case

Geotriggers can be used to notify users when they have entered or exited a geofence by monitoring a given set of features or graphics. They could be used to display contextual information to museum visitors about nearby exhibits, notify hikers when they have wandered off their desired trail, notify dispatchers when service workers arrive at a scene, or more.

How to use the sample

Observe a virtual walking tour of the Santa Barbara Botanic Garden. Information about the user's current Garden Section, as well as information about nearby points of interest within 10 meters will display or be removed from the UI when the user enters or exits the buffer of each feature.

How it works

  1. Create a GeotriggerFeed with a LocationDataSource class (in this case, a SimulatedLocationDataSource).
  2. Create a FeatureFenceParameters class from a ServiceFeatureTable, a buffer distance at which to monitor each feature, an Arcade Expression, and a name for the specific geotrigger.
  3. Create a FenceGeotrigger with the geotrigger feed, a FenceRuleType, and the fence parameters.
  4. Create a GeotriggerMonitor with the fence geotrigger and call GeotriggerMonitor.StartAsync() to begin listening for events that meet the FenceRuleType.
  5. When a GeotriggerMonitor.Notification emits, capture the GeotriggerNotificationInfo.
  6. For more information about the feature that triggered the notification, cast the GeotriggerNotificationInfo to a FenceGeotriggerNotificationInfo and call FenceGeotriggerNotificationInfo..
  7. Depending on the FenceGeotriggerNotificationInfo.FenceNotificationType display or hide information on the UI from the GeoElement's attributes.

Relevant API

  • ArcadeExpression
  • FeatureFenceParameters
  • FenceGeotrigger
  • FenceGeotriggerNotificationInfo
  • FenceRuleType
  • GeoElement
  • Geotrigger
  • GeotriggerFeed
  • GeotriggerMonitor
  • GeotriggerNotificationInfo
  • ServiceFeatureTable
  • SimulatedLocationDataSource

About the data

This sample uses the Santa Barbara Botanic Garden Geotriggers Sample ArcGIS Online Web Map which includes a georeferenced map of the garden as well as select polygon and point features to denote garden sections and points of interest. Description text and attachment images in the feature layers were provided by the Santa Barbara Botanic Garden and more information can be found on the Explore > Sections portion of their website. All assets are used with permission from the Santa Barbara Botanic Garden. For more information, visit the Santa Barbara Botanic Garden website.

Tags

alert, arcade, fence, geofence, geotrigger, location, navigation, notification, notify, routing, trigger

Sample Code

LocationDrivenGeotriggers.xaml.csLocationDrivenGeotriggers.xaml.csLocationDrivenGeotriggers.xaml
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 // 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 Esri.ArcGISRuntime; using Esri.ArcGISRuntime.Data; using Esri.ArcGISRuntime.Geometry; using Esri.ArcGISRuntime.Geotriggers; using Esri.ArcGISRuntime.Location; using Esri.ArcGISRuntime.Mapping; using Esri.ArcGISRuntime.UI;  namespace ArcGIS.Samples.LocationDrivenGeotriggers {  [ArcGIS.Samples.Shared.Attributes.Sample(  name: "Set up location-driven Geotriggers",  category: "Location",  description: "Create a notification every time a given location data source has entered and/or exited a set of features or graphics.",  instructions: "Observe a virtual walking tour of the Santa Barbara Botanic Garden. Information about the user's current Garden Section, as well as information about nearby points of interest within 10 meters will display or be removed from the UI when the user enters or exits the buffer of each feature.",  tags: new[] { "alert", "arcade", "fence", "geofence", "geotrigger", "location", "navigation", "notification", "notify", "routing", "trigger" })]  public partial class LocationDrivenGeotriggers : ContentPage, IDisposable  {  private string _tourPolylineJSON = "{\"paths\":[[[-119.709881177746,34.4570041646846],[-119.709875813328,34.4570152227745],[-119.709869107805,34.4570240692453],[-119.709859720074,34.4570351273326],[-119.709853014551,34.4570539260775],[-119.709847650133,34.4570760422426],[-119.709848991238,34.4570926293626],[-119.70985569676,34.4571103222869],[-119.709873131119,34.4571202745552],[-119.709889224373,34.4571302268223],[-119.709902635418,34.4571357558591],[-119.709910682045,34.4571600836165],[-119.709910682045,34.4571744591062],[-119.709902635418,34.4571833055602],[-119.709889224373,34.4571910462067],[-119.70988251885,34.4571965752394],[-119.70988251885,34.4572032100782],[-119.709889224373,34.4572175855605],[-119.709898612104,34.4572264320099],[-119.709912023149,34.4572341726524],[-119.709901294313,34.4572419132941],[-119.709895929895,34.4572507597409],[-119.709897271,34.4572596061868],[-119.709902635418,34.4572728758539],[-119.709902635418,34.4572828281028],[-119.70990934094,34.457294991961],[-119.709912023149,34.4573038384022],[-119.709886542164,34.4573115790375],[-119.709861061178,34.4573248486963],[-119.709843626819,34.4573414357669],[-119.709836921297,34.4573668692686],[-119.709843626819,34.4573934085666],[-119.709827533565,34.4574055724087],[-119.709791323744,34.4574188420525],[-119.709749749504,34.4574332174977],[-119.709709516369,34.4574431697275],[-119.709734997354,34.4574807670294],[-119.709748062646,34.4575248306656],[-119.709757450378,34.4575635337324],[-119.709770861423,34.457600025179],[-119.709785613572,34.4576387282109],[-119.70980573014,34.4576730080242],[-119.709815117871,34.4577117110223],[-119.709821823394,34.4577504140025],[-119.709821823394,34.4577869053674],[-119.709821823394,34.4578256083127],[-119.70981780008,34.4578609938471],[-119.709819141185,34.457906331541],[-119.70981460448,34.4579890675855],[-119.709818627793,34.4580675790658],[-119.70982667442,34.4581118108532],[-119.709832038838,34.4581471962662],[-119.709834721047,34.4581947453913],[-119.709836062152,34.4582323423548],[-119.709834721047,34.4582787856393],[-119.709805216748,34.4583429215611],[-119.709759619195,34.4584026342716],[-119.709700610597,34.4584612411497],[-119.709645400048,34.4585103926263],[-119.709566274882,34.4585457778704],[-119.709493855239,34.4585944325566],[-119.709458986522,34.458622077252],[-119.709424117805,34.4586198656767],[-119.709386566878,34.4586110193749],[-119.70935438037,34.4586110193749],[-119.709339628221,34.4586231830396],[-119.709324876071,34.4586585682359],[-119.709306100608,34.4586862129101],[-119.709269890786,34.4587171749343],[-119.709244409801,34.4587238096523],[-119.709229657651,34.4587293385835],[-119.709212223293,34.4587459253751],[-119.70919076562,34.4587945799446],[-119.709174672366,34.4588503400161],[-119.709157238008,34.4589288506865],[-119.709153214694,34.4589951976744],[-119.709155896903,34.4590449578807],[-119.70916394353,34.4590958238387],[-119.709186742307,34.4591323146156],[-119.709218928815,34.4591621706939],[-119.709237704278,34.4591831805204],[-119.709241727592,34.4592252001575],[-119.709238133851,34.459258658624],[-119.709219358388,34.4592796684262],[-119.709207288447,34.4592962551085],[-119.709208629552,34.4593084186733],[-119.709271661463,34.4593791884701],[-119.709310553494,34.4594267368937],[-119.709330670062,34.4594510639836],[-119.709353468838,34.4595008239182],[-119.70936285657,34.4595362087426],[-119.709423221989,34.4595943612845],[-119.709455408497,34.4596297460692],[-119.709487595005,34.459665130839],[-119.709507711573,34.4596817174446],[-119.709523804827,34.4596861405389],[-119.709557332439,34.4596894578594],[-119.709586836739,34.4596894578594],[-119.709593542261,34.4596772943501],[-119.709590860052,34.4596496500041],[-119.709572084589,34.4595777746615],[-119.709566720171,34.4595313320996],[-119.709578790112,34.4595136396883],[-119.709590860052,34.4594992646013],[-119.709627069874,34.4594882068404],[-119.709675349636,34.4595567649343],[-119.709735699339,34.4596197941001],[-119.709775932474,34.4596795058974],[-119.709802754564,34.4597126790997],[-119.709832258863,34.4597359003334],[-119.70986712758,34.4597171021923],[-119.70986980979,34.4596839289918],[-119.709865786476,34.4596308518435],[-119.709876515312,34.4595788804365],[-119.70988187973,34.4595346494263],[-119.709879197521,34.4594926299449],[-119.709852375431,34.4594539277723],[-119.709806777878,34.4593953215911],[-119.709767885847,34.4593212344729],[-119.709720947189,34.4592195028005],[-119.709708720088,34.4591478732967],[-119.709710061193,34.4591058536206],[-119.709707378984,34.459079314867],[-119.709652393699,34.4590262373344],[-119.709617524982,34.4589499383221],[-119.709626771268,34.4588695962162],[-119.709683097658,34.4588032491285],[-119.709730036316,34.4587391135603],[-119.709759540615,34.4586993052518],[-119.7097850216,34.4586650258598],[-119.710059948024,34.4587744987075],[-119.710104204473,34.4587932970608],[-119.710128443889,34.4587649224307],[-119.71019415801,34.4587096331253],[-119.710273283176,34.4586731421637],[-119.71031619852,3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  private SimulatedLocationDataSource _simulatedSource;  private LocationGeotriggerFeed _geotriggerFeed;   private ServiceFeatureTable _gardenSections;  private ServiceFeatureTable _gardenPoints;   private GeotriggerMonitor _sectionMonitor;  private GeotriggerMonitor _pointsMonitor;   private List<GeotriggerFeature> _features = new List<GeotriggerFeature>();   private string _currentSection;  private List<string> _pointsOfInterest = new List<string>();   public LocationDrivenGeotriggers()  {  InitializeComponent();  _ = Initialize();  }   private async Task Initialize()  {  try  {  // This sample uses a web map with a predefined tile basemap, feature styles, and labels.  MyMapView.Map = new Map(new Uri("https://www.arcgis.com/home/item.html?id=6ab0e91dc39e478cae4f408e1a36a308"));  await MyMapView.Map.LoadAsync();   // Get service feature tables from the map to create GeotriggerMonitors for.  _gardenSections = ((FeatureLayer)MyMapView.Map.OperationalLayers[0]).FeatureTable as ServiceFeatureTable;  _gardenPoints = ((FeatureLayer)MyMapView.Map.OperationalLayers[2]).FeatureTable as ServiceFeatureTable;   // Create a simulated location data source for simulating a path through the data.  _simulatedSource = new SimulatedLocationDataSource();   // Create SimulationParameters starting at the current time, velocity, and horizontal and vertical accuracy.  SimulationParameters simulationParameters = new SimulationParameters(DateTime.Now, 3.0, 0.0, 0.0);   // Use the polyline as defined above or from this AGOL GeoJSON to define the path. Retrieved from https://https://arcgisruntime.maps.arcgis.com/home/item.html?id=2a346cf1668d4564b8413382ae98a956  _simulatedSource.SetLocationsWithPolyline(Geometry.FromJson(_tourPolylineJSON) as Polyline, simulationParameters);   // Set up the location display.  MyMapView.LocationDisplay.DataSource = _simulatedSource;  MyMapView.LocationDisplay.AutoPanMode = LocationDisplayAutoPanMode.Recenter;  MyMapView.LocationDisplay.InitialZoomScale = 1000;  await _simulatedSource?.StartAsync();   // LocationGeotriggerFeed will be used in instantiating a FenceGeotrigger.  _geotriggerFeed = new LocationGeotriggerFeed(_simulatedSource);   // Create monitors for sections and points of interest.  _sectionMonitor = CreateGeotriggerMonitor(_gardenSections, 0.0, "Section Geotrigger");  _pointsMonitor = CreateGeotriggerMonitor(_gardenPoints, 10.0, "POI Geotrigger");   // Start both Geotrigger monitors.  await _sectionMonitor?.StartAsync();  await _pointsMonitor?.StartAsync();  }  catch (Exception ex)  {  await Application.Current.Windows[0].Page.DisplayAlert(ex.GetType().Name, ex.Message, "OK");  }  }   private GeotriggerMonitor CreateGeotriggerMonitor(ServiceFeatureTable table, double bufferSize, string triggerName)  {  // Create parameters for the fence.  FeatureFenceParameters fenceParameters = new FeatureFenceParameters(table, bufferSize);   // The ArcadeExpression defined in the following FenceGeotrigger returns the value for the "name" field of the feature that triggered the monitor.  FenceGeotrigger fenceTrigger = new FenceGeotrigger(_geotriggerFeed, FenceRuleType.EnterOrExit, fenceParameters, new ArcadeExpression("$fenceFeature.name"), triggerName);   // Create the monitor and set its event handler for notifications.  GeotriggerMonitor geotriggerMonitor = new GeotriggerMonitor(fenceTrigger);  geotriggerMonitor.Notification += HandleGeotriggerNotification;   return geotriggerMonitor;  }   private void HandleGeotriggerNotification(object sender, GeotriggerNotificationInfo info)  {  // The collection used for the list view is changed, and must be modified on a UI thread.  Dispatcher.Dispatch(async () =>  {  if (info is FenceGeotriggerNotificationInfo fenceInfo)  {  if (fenceInfo.FenceNotificationType == FenceNotificationType.Entered)  {  if (!_features.Any(f => f.Name == fenceInfo.Message))  {  try  {  // Get the feature that's fence has been entered.  ArcGISFeature feature = fenceInfo.FenceGeoElement as ArcGISFeature;   // Get the description for the feature.  string description = feature.Attributes["desc_raw"].ToString();   // Get the attachments for the feature.  IReadOnlyList<Attachment> attach = await feature.GetAttachmentsAsync();   // Load the attachment data into an image source.  Stream attachmentDataStream = await attach.First().GetDataAsync();  var imageSource = ImageSource.FromStream(() => attachmentDataStream);   // Create an object to group the information together for interface use.  GeotriggerFeature geotriggerFeature = new GeotriggerFeature  {  Name = fenceInfo.Message,  Description = description,  ImageSource = imageSource,  };   // Add the object to the list of known feature information.  _features.Add(geotriggerFeature);  }  catch (Exception ex)  {  System.Diagnostics.Debug.WriteLine(ex.Message);  }  }   if (fenceInfo.GeotriggerMonitor == _pointsMonitor)  {  _pointsOfInterest.Add(fenceInfo.Message);  }   if (fenceInfo.GeotriggerMonitor == _sectionMonitor)  {  _currentSection = fenceInfo.Message;  }   EventLabel.Text = $"Entered {fenceInfo.Message} fence.";  }  else  {  if (fenceInfo.GeotriggerMonitor == _pointsMonitor)  {  _pointsOfInterest.Remove(fenceInfo.Message);  }  if (fenceInfo.GeotriggerMonitor == _sectionMonitor && _currentSection == fenceInfo.Message)  {  _currentSection = string.Empty;  }   EventLabel.Text = $"Exited {fenceInfo.Message} fence.";  }  }   // Update the UI with the current section and points of interest.  SectionButton.Text = $"Section: {_currentSection}";   if (_pointsOfInterest.Any())  {  POILabel.Text = $"Points of interest: {string.Join(", ", _pointsOfInterest)}";  }  else  {  POILabel.Text = "Points of interest:";  }  });  }   private void DisplayData(GeotriggerFeature feature)  {  // Update the UI with data about the selected feature.  FeatureName.Text = feature.Name;  FeatureImage.Source = feature.ImageSource;  FeatureDescription.Text = feature.Description;  PopupPage.IsVisible = true;  }   private void PlayPauseButton_Pressed(object sender, EventArgs e)  {  // Start and stop the simulated location on a button press.  if (_simulatedSource.Status == LocationDataSourceStatus.Started)  {  _simulatedSource.StopAsync();  PlayPauseButton.Text = "Play";  }  else  {  _simulatedSource.StartAsync();  PlayPauseButton.Text = "Pause";  }  }   private void PopupCloseButton_Clicked(object sender, EventArgs e)  {  PopupPage.IsVisible = false;  }   private void SectionButton_Clicked(object sender, EventArgs e)  {  // Display data for the section the user is currently in.  if (!string.IsNullOrEmpty(_currentSection))  {  DisplayData(_features.First(f => f.Name == _currentSection));  }  }   public void Dispose()  {  // Stop the location data source.  MyMapView?.LocationDisplay?.DataSource?.StopAsync();  }  }   // Class to store attributes of features together.  public class GeotriggerFeature  {  public string Name { get; set; }   public string Description { get; set; }   public ImageSource ImageSource { get; set; }  } }

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