Find closest facility to an incident (interactive)

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Find a route to the closest facility from a location.

Image of find closest facility to an incident interactive

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

Tap near any of the hospitals and a route will be displayed from that tapped location to the nearest hospital.

How it works

  1. Create a ClosestFacilityTask using a Url from an online network analysis service.
  2. Get ClosestFacilityParameters from task, task.createDefaultParametersAsync().get().
  3. Add the list of facilities to parameters, closestFacilityParameters.setFacilities(facilitiesList).
  4. Add the incident to parameters, closestFacilityParameters.setIncidents(Collections.singletonList(new Incident(incidentPoint))).
  5. Get ClosestFacilityResult from solving task with parameters, task.solveClosestFacilityAsync(facilityParameters).get().
  6. Get index list of closet facilities to incident, facilityResult.getRankedFacilitiesIndexes(0).
  7. Get index of closest facility, rankedFacilitiesList.get(0).
  8. Find closest facility route, facilityResult.getRoute(closestFacilityIndex, IncidentIndex).
  9. Display route to MapView:

    • Create Graphic from route geometry, new Graphic(route.getRouteGeometry(), routeSymbol).
    • Add graphic to GraphicsOverlay which is attached to the mapview.

Relevant API

  • ClosestFacilityParameters
  • ClosestFacilityResult
  • ClosestFacilityRoute
  • ClosestFacilityTask
  • Facility
  • Graphic
  • GraphicsOverlay
  • Incident
  • MapView

Tags

incident, network analysis, route, search

Sample Code

MainActivity.java
                                                                                                                                                                                                                           
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/*
 *  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.
 */

package com.esri.arcgisruntime.sample.findclosestfacilitytoanincidentinteractive;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutionException;

import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReference;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.loadable.LoadStatus;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.DefaultMapViewOnTouchListener;
import com.esri.arcgisruntime.mapping.view.Graphic;
import com.esri.arcgisruntime.mapping.view.GraphicsOverlay;
import com.esri.arcgisruntime.mapping.view.MapView;
import com.esri.arcgisruntime.symbology.PictureMarkerSymbol;
import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
import com.esri.arcgisruntime.symbology.SimpleMarkerSymbol;
import com.esri.arcgisruntime.tasks.networkanalysis.ClosestFacilityParameters;
import com.esri.arcgisruntime.tasks.networkanalysis.ClosestFacilityResult;
import com.esri.arcgisruntime.tasks.networkanalysis.ClosestFacilityRoute;
import com.esri.arcgisruntime.tasks.networkanalysis.ClosestFacilityTask;
import com.esri.arcgisruntime.tasks.networkanalysis.Facility;
import com.esri.arcgisruntime.tasks.networkanalysis.Incident;

public class MainActivity extends AppCompatActivity {

  private static final String TAG = MainActivity.class.getSimpleName();

  private final SpatialReference mWebMercator = SpatialReferences.getWebMercator();

  private MapView mMapView;
  private GraphicsOverlay mFacilityGraphicsOverlay;
  private GraphicsOverlay mIncidentGraphicsOverlay;
  private SimpleLineSymbol mRouteSymbol;
  private List<Facility> mFacilities;
  private ClosestFacilityTask mClosestFacilityTask;
  private ClosestFacilityParameters mClosestFacilityParameters;
  private Point mIncidentPoint;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // authentication with an API key or named user is required to access basemaps and other
    // location services
    ArcGISRuntimeEnvironment.setApiKey(BuildConfig.API_KEY);

    // get a reference to the map view
    mMapView = findViewById(R.id.mapView);

    // create a map with a streets basemap
    ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_STREETS);

    // add the map to the map view
    mMapView.setMap(map);

    // set the view point to center on San Diego
    mMapView.setViewpoint(new Viewpoint( 32.727, -117.1750, 100000));

    mFacilityGraphicsOverlay = new GraphicsOverlay();
    mIncidentGraphicsOverlay = new GraphicsOverlay();
    createFacilitiesAndGraphics();

    // add graphics overlays to the map view
    mMapView.getGraphicsOverlays().add(mFacilityGraphicsOverlay);
    mMapView.getGraphicsOverlays().add(mIncidentGraphicsOverlay);

    // task to find the closest route between an incident and a facility
    mClosestFacilityTask = new ClosestFacilityTask(this, getString(R.string.san_diego_network_service_url));
    mClosestFacilityTask.addDoneLoadingListener(() -> {
      if (mClosestFacilityTask.getLoadStatus() == LoadStatus.LOADED) {
        ListenableFuture<ClosestFacilityParameters> closestFacilityParametersFuture = mClosestFacilityTask
            .createDefaultParametersAsync();
        closestFacilityParametersFuture.addDoneListener(() -> {
          try {
            mClosestFacilityParameters = closestFacilityParametersFuture.get();
            // set new parameters to find route
            mClosestFacilityParameters.setFacilities(mFacilities);
          } catch (ExecutionException | InterruptedException e) {
            String error = "Error generating parameters: " + e.getMessage();
            Log.e(TAG, error);
            Toast.makeText(this, error, Toast.LENGTH_LONG).show();
          }
        });
      } else {
        String error = "Closest facility task failed to load: " + mClosestFacilityTask.getLoadError().getMessage();
        Log.e(TAG, error);
        Toast.makeText(this, error, Toast.LENGTH_LONG).show();
      }
    });
    mClosestFacilityTask.loadAsync();

    // symbols that display incident (black cross) and route (blue line) to view
    SimpleMarkerSymbol incidentSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.CROSS, Color.BLACK, 20);
    mRouteSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, Color.BLUE, 2.0f);

    // place incident were user clicks and display route to closest facility
    mMapView.setOnTouchListener(new DefaultMapViewOnTouchListener(this, mMapView) {
      @Override public boolean onSingleTapConfirmed(MotionEvent e) {
        // remove last incident
        mIncidentGraphicsOverlay.getGraphics().clear();
        // show incident to the map view
        Point mapPoint = mMapView
            .screenToLocation(new android.graphics.Point(Math.round(e.getX()), Math.round(e.getY())));
        mIncidentPoint = new Point(mapPoint.getX(), mapPoint.getY(), mWebMercator);
        Graphic graphic = new Graphic(mIncidentPoint, incidentSymbol);
        mIncidentGraphicsOverlay.getGraphics().add(graphic);
        populateParametersAndSolveRoute();
        return true;
      }
    });
  }

  /**
   * Creates facilities around the San Diego region. Facilities are created using point geometry which is then used to
   * make graphics for the graphics overlay.
   */
  private void createFacilitiesAndGraphics() {
    // list of known facilities in the San Diego area
    mFacilities = Arrays.asList(
        new Facility(new Point(-1.3042129900625112E7, 3860127.9479775648, mWebMercator)),
        new Facility(new Point(-1.3042193400557665E7, 3862448.873041752, mWebMercator)),
        new Facility(new Point(-1.3046882875518233E7, 3862704.9896770366, mWebMercator)),
        new Facility(new Point(-1.3040539754780494E7, 3862924.5938606677, mWebMercator)),
        new Facility(new Point(-1.3042571225655518E7, 3858981.773018156, mWebMercator)),
        new Facility(new Point(-1.3039784633928463E7, 3856692.5980474586, mWebMercator)),
        new Facility(new Point(-1.3049023883956768E7, 3861993.789732541, mWebMercator)));

    // image for displaying facility
    String facilityUrl = getString(R.string.hospital_symbol_url);
    PictureMarkerSymbol facilitySymbol = new PictureMarkerSymbol(facilityUrl);
    facilitySymbol.setHeight(30);
    facilitySymbol.setWidth(30);

    // for each facility, create a graphic and add to graphics overlay
    for (Facility facility : mFacilities) {
      mFacilityGraphicsOverlay.getGraphics().add(new Graphic(facility.getGeometry(), facilitySymbol));
    }
  }

  /**
   * Adds facilities (hospitals) and user's incident (black cross) to closest facility parameters, which will be used to
   * display the closest route from the user's incident to its' nearest facility.
   */
  private void populateParametersAndSolveRoute() {
    mClosestFacilityParameters.setIncidents(Collections.singletonList(new Incident(mIncidentPoint)));

    // find closest route using parameters from above
    ListenableFuture<ClosestFacilityResult> closestFacilityResultFuture = mClosestFacilityTask
        .solveClosestFacilityAsync(mClosestFacilityParameters);
    closestFacilityResultFuture.addDoneListener(() -> {
      try {
        ClosestFacilityResult facilityResult = closestFacilityResultFuture.get();
        // a list of closest facilities based on users incident
        List<Integer> rankedList = facilityResult.getRankedFacilityIndexes(0);
        // get the index of the closest facility to incident
        int closestFacility = rankedList.get(0);
        // get route from incident to closest facility and display to map view
        ClosestFacilityRoute route = facilityResult.getRoute(closestFacility, 0);
        mIncidentGraphicsOverlay.getGraphics().add(new Graphic(route.getRouteGeometry(), mRouteSymbol));
      } catch (ExecutionException | InterruptedException e) {
        String error;
        error = e.getMessage().contains("Unable to complete operation") ?
            "Incident not within the San Diego Area!" :
            "Error getting closest facility result: " + e.getMessage();
        Log.e(TAG, error);
        Toast.makeText(this, error, Toast.LENGTH_LONG).show();
      }
    });
  }

  @Override
  protected void onPause() {
    mMapView.pause();
    super.onPause();
  }

  @Override
  protected void onResume() {
    super.onResume();
    mMapView.resume();
  }

  @Override
  protected void onDestroy() {
    mMapView.dispose();
    super.onDestroy();
  }
}

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