Set up location-driven Geotriggers

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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.

screenshot

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 with a ServiceFeatureTable and a buffer distance at which to monitor each feature.
  3. Create a FenceGeotrigger with the geotrigger feed, a FenceRuleType, the fence parameters, an Arcade Expression, and a name for the specific geotrigger.
  4. Create a GeotriggerMonitor with the fence geotrigger and call GeotriggerMonitor::start() to begin listening for events that meet the FenceRuleType.
  5. When a GeotriggerMonitor::geotriggerNotification emits, capture the GeotriggerNotificationInfo.
  6. For more information about the feature that triggered the notification, cast the GeotriggerNotificationInfo to a FenceGeotriggerNotificationInfo and call FenceGeotriggerNotificationInfo::fenceGeoElement().
  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 Garden Sections & Displays 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

Geotriggers.cppGeotriggers.cppGeotriggers.hFeatureInfoPane.qmlGeotriggers.qml
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// [WriteFile Name=Geotriggers, Category=Analysis]
// [Legal]
// Copyright 2021 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.
// [Legal]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "Geotriggers.h"

#include "ArcadeExpression.h"
#include "FenceGeotrigger.h"
#include "FenceGeotriggerNotificationInfo.h"
#include "GeotriggerNotificationInfo.h"
#include "GeotriggerMonitor.h"
#include "GeotriggersTypes.h"
#include "FeatureFenceParameters.h"
#include "LocationGeotriggerFeed.h"
#include "Map.h"
#include "MapQuickView.h"
#include "PortalItem.h"
#include "ServiceFeatureTable.h"
#include "SimulatedLocationDataSource.h"
#include "SimulationParameters.h"

using namespace Esri::ArcGISRuntime;

namespace
{
const QString walkingTourPolyineJson("{\"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],[-119.710273283176,34.45867314216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const QString sectionGeotriggerName = "Section Geotrigger";
const QString poiGeotriggerName = "POI Geotrigger";
}

Geotriggers::Geotriggers(QObject* parent /* = nullptr */):
  QObject(parent)
{
  // This sample uses a web map with a predefined tile basemap, feature styles, and labels
  m_map = new Map(new PortalItem("6ab0e91dc39e478cae4f408e1a36a308", this), this);

  // Instantiate the service feature tables to later create GeotriggerMonitors for
  m_gardenSections = new ServiceFeatureTable(new PortalItem("1ba816341ea04243832136379b8951d9", this), 0, this);
  m_gardenPois = new ServiceFeatureTable(new PortalItem("7c6280c290c34ae8aeb6b5c4ec841167", this), 0, this);
}

Geotriggers::~Geotriggers() = default;

void Geotriggers::init()
{
  // Register the map view for QML
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<Geotriggers>("Esri.Samples", 1, 0, "GeotriggersSample");
}

// Create READ functions for Q_PROPERTIES like the information about sections and POIs
MapQuickView* Geotriggers::mapView() const
{
  return m_mapView;
}

QString Geotriggers::currentSection() const
{
  if (!m_currentFeaturesEntered[sectionGeotriggerName].isEmpty())
    return m_currentFeaturesEntered[sectionGeotriggerName].last();

  return "N/A";
}

QStringList Geotriggers::poisInRange() const
{
  return m_currentFeaturesEntered[poiGeotriggerName];
}

QString Geotriggers::currentDescription() const
{
  return m_currentFeatureDescription;
}

QUrl Geotriggers::currentImageUrl() const
{
  return m_currentFeatureImageUrl;
}

// Set the map view - once that is done we can instantiate the location display and geotrigger monitors
void Geotriggers::setMapView(MapQuickView* mapView)
{
  if (!mapView || mapView == m_mapView)
    return;

  m_mapView = mapView;
  m_mapView->setMap(m_map);

  emit mapViewChanged();

  // Start the simulated location display data source and create a LocationGeotriggerFeed that will be required in createGeotriggerMonitor()
  initializeSimulatedLocationDisplay();

  // Create geotriggers for each of the service feature tables
  createGeotriggerMonitor(m_gardenSections, 0.0, sectionGeotriggerName);
  createGeotriggerMonitor(m_gardenPois, 10.0, poiGeotriggerName);
}

void Geotriggers::initializeSimulatedLocationDisplay()
{
  m_simulatedLocationDataSource = new SimulatedLocationDataSource(this);

  // Create SimulationParameters starting at the current time, a velocity of 5 m/s, and a horizontal and vertical accuracy of 0.0
  SimulationParameters* simulationParameters = new SimulationParameters(QDateTime::currentDateTime(), 5.0, 0.0, 0.0, this);

  // 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
  m_simulatedLocationDataSource->setLocationsWithPolyline(Polyline::fromJson(walkingTourPolyineJson), simulationParameters);

  m_mapView->locationDisplay()->setDataSource(m_simulatedLocationDataSource);
  m_mapView->locationDisplay()->setAutoPanMode(LocationDisplayAutoPanMode::Recenter);
  m_mapView->locationDisplay()->setInitialZoomScale(1000);
  m_mapView->locationDisplay()->start();

  m_simulatedLocationDataSource->start();

  // LocationGeotriggerFeed will be used in instantiating a FenceGeotrigger in createGeotriggerMonitor()
  m_geotriggerFeed = new LocationGeotriggerFeed(m_simulatedLocationDataSource, this);
}

// This function is used to create two geotrigger monitors in this sample - one for the sections and one for the points of interest
// The parameters for this function are the only differences between the two geotrigger monitors
void Geotriggers::createGeotriggerMonitor(ServiceFeatureTable* serviceFeatureTable, double bufferSize, const QString& geotriggerName)
{
  FeatureFenceParameters* featureFenceParameters = new FeatureFenceParameters(serviceFeatureTable, bufferSize, this);
  // The ArcadeExpression defined in the following FenceGeotrigger returns the value for the "name" field of the feature that triggered the monitor
  FenceGeotrigger* fenceGeotrigger = new FenceGeotrigger(m_geotriggerFeed, FenceRuleType::EnterOrExit, featureFenceParameters, new ArcadeExpression("$fencefeature.name", this), geotriggerName, this);
  GeotriggerMonitor* geotriggerMonitor = new GeotriggerMonitor(fenceGeotrigger, this);

  connect(geotriggerMonitor, &GeotriggerMonitor::geotriggerNotification, this, &Geotriggers::handleGeotriggerNotification);

  // Start must be explicitly called. It is called after the signal connection is defined to avoid a race condition in Qt.
  geotriggerMonitor->start();
}

void Geotriggers::handleGeotriggerNotification(GeotriggerNotificationInfo* geotriggerNotificationInfo)
{
  // Create a QScopedPointer so GeotriggerNotificationInfo does not persist outside this scope
  QScopedPointer<GeotriggerNotificationInfo> scopedNotification(geotriggerNotificationInfo);

  // GeotriggerNotificationInfo provides access to information about the geotrigger that was triggered
  QString geotriggerName = geotriggerNotificationInfo->geotriggerMonitor()->geotrigger()->name();

  // message() returns the evaluated arcade expression defined in the FenceGeotrigger, "$fencefeatue.name" in this case
  QString featureName = geotriggerNotificationInfo->message();

  // FenceGeotriggerNotificationInfo provides access to the feature that triggered the notification
  FenceGeotriggerNotificationInfo* fenceGeotriggerNotificationInfo = static_cast<FenceGeotriggerNotificationInfo*>(geotriggerNotificationInfo);
  GeoElement* fenceGeoElement = fenceGeotriggerNotificationInfo->fenceGeoElement();

  ArcGISFeature* fenceFeature = dynamic_cast<ArcGISFeature*>(fenceGeoElement);

  if (fenceGeotriggerNotificationInfo->fenceNotificationType() == FenceNotificationType::Entered)
  {
    // If the user enters a given geofence, add the feature's information to the UI and save the feature for querying.
    m_currentFeaturesEntered[geotriggerName].append(featureName);

    if (!m_featureQMap.contains(featureName))
    {
      // Set the parent to the Geotriggers QObject so the feature is still available outside the scope of this function
      fenceFeature->setParent(this);
      m_featureQMap[featureName] = fenceFeature;
    }
  }
  else
  {
    // If the user leaves the geofence, remove the information from the UI
    m_currentFeaturesEntered[geotriggerName].removeAll(featureName);
  }

  emit displayInfoChanged();
}

void Geotriggers::getFeatureInformation(const QString& sectionName)
{
  // Recenter the camera on the user if need be
  m_mapView->locationDisplay()->setAutoPanMode(LocationDisplayAutoPanMode::Recenter);

  // Clear feature description and image of the previous query
  m_currentFeatureImageUrl = QUrl("");

  QMap<QString, ArcGISFeature*>::iterator findIt = m_featureQMap.find(sectionName);

  if (findIt == m_featureQMap.end())
  {
    m_currentFeatureDescription = "Unable to find information for this Garden feature.";
    emit displayInfoChanged();
    return;
  }

  ArcGISFeature* feature = *findIt;
  m_currentFeatureDescription = feature->attributes()->attributeValue("description").toString();

  if (m_featureAttachmentImageUrls.contains(sectionName))
  {
    m_currentFeatureImageUrl = m_featureAttachmentImageUrls[sectionName];
    emit displayInfoChanged();
    return;
  }

  emit displayInfoChanged();

  AttachmentListModel* featureAttachments = feature->attachments();

  // Fetch attachments will automatically trigger upon instantiation of the AttachmentListModel
  connect(featureAttachments, &AttachmentListModel::fetchAttachmentsCompleted, this, [this, sectionName](QUuid, const QList<Attachment*> attachments)
  {
    if (attachments.isEmpty())
      return;

    // Get the first (and only) attachment for the feature
    Attachment* sectionImageAttachment = attachments.first();

    connect(sectionImageAttachment, &Attachment::fetchDataCompleted, this, [this, sectionImageAttachment, sectionName]()
    {
      m_featureAttachmentImageUrls[sectionName] = sectionImageAttachment->attachmentUrl();
      m_currentFeatureImageUrl = m_featureAttachmentImageUrls[sectionName];
      emit displayInfoChanged();
    });

    sectionImageAttachment->fetchData();
  });
}

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