Find a route to the closest facility from a location.
Use case
Quickly and accurately determining the most efficient route between a location and a facility is a frequently encountered task. For example, a paramedic may need to know which hospital in the vicinity offers the possibility of getting an ambulance patient critical medical care in the shortest amount of time. Solving for the closest hospital to the ambulance's location using an impedance of "travel time" would provide this information.
How to use the sample
Click near any of the hospitals and a route will be displayed from that clicked location to the nearest hospital.
How it works
- Create a
ClosestFacilityTaskusing an Url from an online service. - Get a
ClosestFacilityParametersfrom this task, usingcreateDefaultParameters. - Add a list of facilities to the task parameters, using
ClosestFacilityParameters.setFacilities. - Add an incident to the parameters, using
ClosestFacilityParameters.setIncidents(. - Get the
ClosestFacilityResultfrom solving the task with parameters: ,ClosestFacilityTask.solveClosestFacility. - Get the ranked list of the indices of the closest facilities to the incident,
ClosestFacilityResult.rankedFacilities. - Get the index of the closest facility (e.g. the first index in the ranked list).
- Find the closest facility route,
ClosestFacilityResult.route. - Display the route on the
MapView:
- create a
Graphicfrom the route geometry,route.routeGeometry. - add graphic to
GraphicsOverlaywhich is attached to the mapview.
Relevant API
- ClosestFacilityParameters
- ClosestFacilityResult
- ClosestFacilityRoute
- ClosestFacilityTask
- Facility
- Graphic
- GraphicsOverlay
- Incident
- MapView
Tags
incident, network analysis, route, search
Sample Code
ClosestFacility.qml
// [WriteFile Name=FindClosestFacilityToAnIncidentInteractive, Category=Routing]
// [Legal]
// Copyright 2017 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]
import QtQuick
import QtQuick.Controls
import Esri.ArcGISRuntime
Rectangle {
id: rootRectangle
clip: true
width: 800
height: 600
property bool busy: false
property string message: ""
property var facilities: []
property var facilityParams: null
// Map view UI presentation at top
MapView {
id: mapView
anchors.fill: parent
Component.onCompleted: {
// Set the focus on MapView to initially enable keyboard navigation
forceActiveFocus();
}
Map {
Basemap {
initStyle: Enums.BasemapStyleArcGISStreets
}
initialViewpoint: ViewpointCenter {
Point {
x: -13041154
y: 3858170
spatialReference: SpatialReference { wkid: 3857 }
}
targetScale: 1e5
}
onLoadStatusChanged: {
createFacilities();
task.load();
}
}
GraphicsOverlay {
id: facilitiesOverlay
SimpleRenderer {
PictureMarkerSymbol {
url: "https://static.arcgis.com/images/Symbols/SafetyHealth/Hospital.png"
height: 30
width: 30
}
}
Graphic {
geometry: Point {
x: -1.3042129900625112E7
y: 3860127.9479775648
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3042129900625112E7
y: 3860127.9479775648
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3042193400557665E7
y: 3862448.873041752
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3046882875518233E7
y: 3862704.9896770366
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3040539754780494E7
y: 3862924.5938606677
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3042571225655518E7
y: 3858981.773018156
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3039784633928463E7
y: 3856692.5980474586
spatialReference: SpatialReference { wkid: 3857 }
}
}
Graphic {
geometry: Point {
x: -1.3049023883956768E7
y: 3861993.789732541
spatialReference: SpatialReference { wkid: 3857 }
}
}
}
GraphicsOverlay {
id: resultsOverlay
}
onMouseClicked: mouse => {
if (busy === true)
return;
if (facilityParams === null)
return;
resultsOverlay.graphics.clear();
const incidentGraphic = ArcGISRuntimeEnvironment.createObject("Graphic", {
geometry: mouse.mapPoint,
symbol: incidentSymbol
});
resultsOverlay.graphics.append(incidentGraphic);
solveRoute(mouse.mapPoint);
}
}
SimpleMarkerSymbol {
id: incidentSymbol
style: Enums.SimpleMarkerSymbolStyleCross
color: "black"
size: 20
}
SimpleLineSymbol {
id: routeSymbol
style: Enums.SimpleLineSymbolStyleSolid
color: "blue"
width: 2.0
}
ClosestFacilityTask {
id: task
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/NAServer/ClosestFacility"
onLoadStatusChanged: {
if (loadStatus !== Enums.LoadStatusLoaded)
return;
setupRouting();
}
onCreateDefaultParametersStatusChanged: {
if (createDefaultParametersStatus !== Enums.TaskStatusCompleted)
return;
busy = false;
facilityParams = createDefaultParametersResult;
facilityParams.setFacilities(facilities);
}
onSolveClosestFacilityStatusChanged: {
if (solveClosestFacilityStatus !== Enums.TaskStatusCompleted)
return;
busy = false;
if (solveClosestFacilityResult === null || solveClosestFacilityResult.error)
message = "Incident not within San Diego Area!";
const rankedList = solveClosestFacilityResult.rankedFacilityIndexes(0);
const closestFacilityIdx = rankedList[0];
const incidentIndex = 0; // 0 since there is just 1 incident at a time
const route = solveClosestFacilityResult.route(closestFacilityIdx, incidentIndex);
const routeGraphic = ArcGISRuntimeEnvironment.createObject("Graphic", {
geometry: route.routeGeometry,
symbol: routeSymbol
});
resultsOverlay.graphics.append(routeGraphic);
}
onErrorChanged: message = error.message;
}
BusyIndicator {
anchors.centerIn: parent
running: busy
}
Dialog {
modal: true
x: Math.round(parent.width - width) / 2
y: Math.round(parent.height - height) / 2
standardButtons: Dialog.Ok
title: "Route Error"
visible: text.length > 0
property alias text : textLabel.text
Text {
id: textLabel
text: message
}
}
function createFacilities() {
facilitiesOverlay.graphics.forEach(graphic => facilities.push(ArcGISRuntimeEnvironment.createObject("Facility", {
geometry: graphic.geometry
})));
}
function setupRouting() {
busy = true;
message = "";
task.createDefaultParameters();
}
function solveRoute(incidentPoint) {
const incident = ArcGISRuntimeEnvironment.createObject("Incident", {geometry: incidentPoint});
facilityParams.setIncidents( [ incident ] );
busy = true;
message = "";
task.solveClosestFacility(facilityParams);
}
}