Find closest facility to multiple incidents (service)

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QML

C++

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Sample viewer app

Find routes from several locations to the respective closest facility.

screenshot

Use case

Quickly and accurately determining the most efficient route between a location and a facility is a frequently encountered task. For example, a city's fire department may need to know which fire stations in the vicinity offer the quickest routes to multiple fires. Solving for the closest fire station to the fire's location using an impedance of "travel time" would provide this information.

How to use the sample

Click 'Solve Routes' to solve and display the route from each incident (fire) to the nearest facility (fire station). Click 'Reset' to clear the results.

How it works

Create a ClosestFacilityTask using a URL from an online service.
Get the default set of ClosestFacilityParameters from the task: closestFacilityTask.createDefaultParameters().
Create ServiceFeatureTables for both facilities incidents.
Add all facilities to the task parameters: closestFacilityParameters.setFacilitiesWithFeatureTable(facilitiesFeatureTable, parameters).
Add all incidents to the task parameters: closestFacilityParameters.setIncidentsWithFeatureTable(incidentsFeatureTable, parameters).
Get ClosestFacilityResult by solving the task with the provided parameters: closestFacilityTask.solveClosestFacility(closestFacilityParameters).
Find the closest facility for each incident by iterating over the list of Incidents.
Display the route as a Graphic using the closestFacilityRoute.routeGeometry().

Relevant API

ClosestFacilityParameters
ClosestFacilityResult
ClosestFacilityRoute
ClosestFacilityTask
Facility
Graphic
GraphicsOverlay
Incident

Sample Code

FindClosestFacilityToMultipleIncidentsService.cppFindClosestFacilityToMultipleIncidentsService.cppFindClosestFacilityToMultipleIncidentsService.hFindClosestFacilityToMultipleIncidentsService.qml
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// [WriteFile Name=FindClosestFacilityToMultipleIncidentsService, Category=Routing]
// [Legal]
// Copyright 2019 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 "FindClosestFacilityToMultipleIncidentsService.h"

#include "Map.h"
#include "MapQuickView.h"
#include "PictureMarkerSymbol.h"
#include "SimpleLineSymbol.h"
#include "SimpleRenderer.h"
#include "ServiceFeatureTable.h"
#include "FeatureLayer.h"
#include "GraphicsOverlay.h"
#include "Graphic.h"
#include "TaskWatcher.h"
#include "GeometryEngine.h"
#include "ClosestFacilityTask.h"
#include "ClosestFacilityParameters.h"
#include "ClosestFacilityResult.h"
#include "ClosestFacilityRoute.h"
#include "MapTypes.h"
#include "SymbolTypes.h"
#include "TaskWatcher.h"
#include "Error.h"
#include "GraphicsOverlayListModel.h"
#include "GraphicListModel.h"
#include "LayerListModel.h"
#include "QueryParameters.h"
#include "Polyline.h"
#include "Envelope.h"

#include <QUuid>

using namespace Esri::ArcGISRuntime;

FindClosestFacilityToMultipleIncidentsService::FindClosestFacilityToMultipleIncidentsService(QObject* parent /* = nullptr */):
  QObject(parent),
  m_map(new Map(BasemapStyle::ArcGISStreetsRelief, this)),
  m_task(new ClosestFacilityTask(QUrl("https://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/NAServer/ClosestFacility"), this)),
  m_resultsOverlay(new GraphicsOverlay(this))
{
  // enable busy indicator while loading
  m_busy = true;

  createSymbols();

  createFeatureLayers();

  connect(m_task, &ClosestFacilityTask::doneLoading, this, [this](Error e)
  {
    if (!e.isEmpty())
    {
      qDebug() << e.message();
      return;
    }
    setupRouting();
  });
  m_task->load();
}

FindClosestFacilityToMultipleIncidentsService::~FindClosestFacilityToMultipleIncidentsService() = default;

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

MapQuickView* FindClosestFacilityToMultipleIncidentsService::mapView() const
{
  return m_mapView;
}

// Set the view (created in QML)
void FindClosestFacilityToMultipleIncidentsService::setMapView(MapQuickView* mapView)
{
  if (!mapView || mapView == m_mapView)
    return;

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

  emit mapViewChanged();
}

void FindClosestFacilityToMultipleIncidentsService::createSymbols()
{
  m_facilitySymbol = new PictureMarkerSymbol(QUrl("https://static.arcgis.com/images/Symbols/SafetyHealth/FireStation.png"), this);
  m_facilitySymbol->setWidth(30.0f);
  m_facilitySymbol->setHeight(30.0f);

  m_incidentSymbol = new PictureMarkerSymbol(QUrl("https://static.arcgis.com/images/Symbols/SafetyHealth/esriCrimeMarker_56_Gradient.png"), this);
  m_incidentSymbol->setWidth(30.0f);
  m_incidentSymbol->setHeight(30.0f);

  m_routeSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle::Solid, Qt::blue, 2.0f, this);
}

void FindClosestFacilityToMultipleIncidentsService::createFeatureLayers()
{
  m_facilitiesFeatureTable = new ServiceFeatureTable(QUrl("https://services2.arcgis.com/ZQgQTuoyBrtmoGdP/ArcGIS/rest/services/San_Diego_Facilities/FeatureServer/0"), this);
  m_facilitiesFeatureLayer = new FeatureLayer(m_facilitiesFeatureTable, this);
  m_facilitiesFeatureLayer->setRenderer(new SimpleRenderer(m_facilitySymbol, this));

  m_incidentsFeatureTable = new ServiceFeatureTable(QUrl("https://services2.arcgis.com/ZQgQTuoyBrtmoGdP/ArcGIS/rest/services/San_Diego_Incidents/FeatureServer/0"), this);
  m_incidentsFeatureLayer = new FeatureLayer(m_incidentsFeatureTable, this);
  m_incidentsFeatureLayer->setRenderer(new SimpleRenderer(m_incidentSymbol, this));

  // connect to the doneLoading signal which calls the slot to set the view point geometry
  connect(m_facilitiesFeatureTable, &ServiceFeatureTable::doneLoading, this, &FindClosestFacilityToMultipleIncidentsService::setViewpointGeometry);
  connect(m_incidentsFeatureTable, &ServiceFeatureTable::doneLoading, this, &FindClosestFacilityToMultipleIncidentsService::setViewpointGeometry);

  m_facilitiesFeatureTable->load();
  m_incidentsFeatureTable->load();
}

void FindClosestFacilityToMultipleIncidentsService::setupRouting()
{
  connect(m_task, &ClosestFacilityTask::createDefaultParametersCompleted, this, [this](QUuid, const ClosestFacilityParameters& defaultParameters)
  {
    QueryParameters params;
    params.setWhereClause("1=1");
    m_facilityParams = defaultParameters;
    m_facilityParams.setFacilitiesWithFeatureTable(m_facilitiesFeatureTable, params);
    m_facilityParams.setIncidentsWithFeatureTable(m_incidentsFeatureTable, params);

    m_busy = false;
    m_solveButtonEnabled = true;
    emit busyChanged();
    emit solveButtonChanged();
  });

  connect(m_task, &ClosestFacilityTask::solveClosestFacilityCompleted, this, [this](QUuid, const ClosestFacilityResult& closestFacilityResult)
  {
    if (closestFacilityResult.isEmpty())
    {
      qDebug() << "Empty result";
      return;
    }

    // finding the closest facility for each incident to create a route graphic between each pair
    for (int incidentIndex = 0; incidentIndex < m_incidentsFeatureTable->numberOfFeatures(); incidentIndex++)
    {
      const auto indexes = closestFacilityResult.rankedFacilityIndexes(incidentIndex);
      const int closestFacilityIndex = indexes.first();
      const ClosestFacilityRoute route = closestFacilityResult.route(closestFacilityIndex, incidentIndex);
      Graphic* m_routeGraphic = new Graphic(route.routeGeometry(), m_routeSymbol, this);

      m_resultsOverlay->graphics()->append(m_routeGraphic);
    }

    m_mapView->graphicsOverlays()->append(m_resultsOverlay);
    m_resetButtonEnabled = true;
    emit resetButtonChanged();
    m_busy = false;
    emit busyChanged();
  });

  m_task->createDefaultParameters();
}

void FindClosestFacilityToMultipleIncidentsService::setViewpointGeometry(const Error& e)
{
  if (!e.isEmpty())
  {
    qDebug() << e.message();
    return;
  }

  // proceed only if both layers have been loaded
  if ((m_facilitiesFeatureTable->loadStatus() != LoadStatus::Loaded) || (m_incidentsFeatureTable->loadStatus() != LoadStatus::Loaded))
    return;

  // return if set viewpoint task watcher has already been created
  if (setViewpointTaskWatcher.isValid())
    return;

  m_mapView->map()->operationalLayers()->append(m_facilitiesFeatureLayer);
  m_mapView->map()->operationalLayers()->append(m_incidentsFeatureLayer);

  setViewpointTaskWatcher = m_mapView->setViewpointGeometry(GeometryEngine::unionOf(m_facilitiesFeatureLayer->fullExtent(), m_incidentsFeatureLayer->fullExtent()), 20);
}

void FindClosestFacilityToMultipleIncidentsService::solveRoute()
{
  m_busy = true;
  m_solveButtonEnabled = false;
  emit busyChanged();
  emit solveButtonChanged();

  m_task->solveClosestFacility(m_facilityParams);
}

void FindClosestFacilityToMultipleIncidentsService::resetGO()
{
  m_mapView->graphicsOverlays()->clear();
  m_resetButtonEnabled = false;
  m_solveButtonEnabled = true;
  emit solveButtonChanged();
  emit resetButtonChanged();
}

ArcGIS Maps SDK for QtC++ samples

Find closest facility to multiple incidents (service)

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ArcGIS Maps SDK for QtC++ samples

Find closest facility to multiple incidents (service)

Use case

How to use the sample

How it works

Relevant API

Tags

Sample Code

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