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GraphicsOverlayExtent Property

Gets the extent of the GraphicsOverlay.

Namespace:  Esri.ArcGISRuntime.UI
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.11.0
Syntax
public Envelope Extent { get; }

Property Value

Type: Envelope
The extent of the GraphicsOverlay.
Examples

WPF

Example Name: FindServiceAreasForMultipleFacilities

Find the service areas of several facilities from a feature service.

Code example screen shot.

C#
// 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.

using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks.NetworkAnalysis;
using Esri.ArcGISRuntime.UI;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace ArcGISRuntime.WPF.Samples.FindServiceAreasForMultipleFacilities
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Find service areas for multiple facilities",
        category: "Network analysis",
        description: "Find the service areas of several facilities from a feature service.",
        instructions: "Click 'find service area' to calculate and display the service area of each facility on the map. The polygons displayed around each facility represents the service area; in red is the area that is within 3 minutes away from the hospital by car. Light orange is the area that is within 5 minutes away from the hospital by car.",
        tags: new[] { "facilities", "feature service", "impedance", "network analysis", "service area", "travel time" })]
    [ArcGISRuntime.Samples.Shared.Attributes.OfflineData()]
    public partial class FindServiceAreasForMultipleFacilities
    {
        // URLs to resources used by the sample.
        private const string NetworkAnalysisUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/NAServer/ServiceArea";
        private const string FacilitiesFeatureUrl = "https://services2.arcgis.com/ZQgQTuoyBrtmoGdP/ArcGIS/rest/services/San_Diego_Facilities/FeatureServer/0";
        private const string IconUrl = "https://static.arcgis.com/images/Symbols/SafetyHealth/Hospital.png";

        // The table that contains the facilities.
        private ServiceFeatureTable _facilitiesTable;

        // The task for performing the service area analysis.
        private ServiceAreaTask _serviceAreaTask;

        // The graphics overlay for displaying the resulting polygons.
        private GraphicsOverlay _resultOverlay;

        // Symbology for the resulting service areas.
        private List<SimpleFillSymbol> _fillSymbols;

        public FindServiceAreasForMultipleFacilities()
        {
            InitializeComponent();
            Initialize();
        }

        private async void Initialize()
        {
            try
            {
                // Create the map and show it in the view.
                Map newMap = new Map(BasemapStyle.ArcGISLightGray);
                MyMapView.Map = newMap;

                // Create the table containing the facilities.
                _facilitiesTable = new ServiceFeatureTable(new Uri(FacilitiesFeatureUrl));

                // Create the layer for rendering the facilities table.
                FeatureLayer facilitiesLayer = new FeatureLayer(_facilitiesTable);

                // Create a simple renderer that will display an image for each facility.
                facilitiesLayer.Renderer = new SimpleRenderer(new PictureMarkerSymbol(new Uri(IconUrl)));

                // Add the layer to the map.
                newMap.OperationalLayers.Add(facilitiesLayer);

                // Create the graphics overlay for displaying the result polygons.
                _resultOverlay = new GraphicsOverlay();

                // Add the result overlay to the view.
                MyMapView.GraphicsOverlays.Add(_resultOverlay);

                // Create a list of fill symbols for rendering the results.
                _fillSymbols = new List<SimpleFillSymbol>();
                _fillSymbols.Add(new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, Color.FromArgb(0x66, 0xFF, 0xA5, 0x00), null));
                _fillSymbols.Add(new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, Color.FromArgb(0x66, 0xFF, 0x00, 0x00), null));

                // Wait for the table to load and zoom to its extent.
                await _facilitiesTable.LoadAsync();
                await MyMapView.SetViewpointGeometryAsync(_facilitiesTable.Extent, 50);

                // Enable the button now that the sample is ready.
                ServiceAreaButton.IsEnabled = true;
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
                ShowMessage("Error", "Error starting the sample.");
            }
        }

        private async Task FindServiceAreas()
        {
            try
            {
                // Create the service area task.
                _serviceAreaTask = await ServiceAreaTask.CreateAsync(new Uri(NetworkAnalysisUrl));

                // Create the default parameters for the service.
                ServiceAreaParameters serviceAreaParameters = await _serviceAreaTask.CreateDefaultParametersAsync();

                // Configure the service area parameters.
                serviceAreaParameters.PolygonDetail = ServiceAreaPolygonDetail.High;
                serviceAreaParameters.ReturnPolygons = true;
                serviceAreaParameters.DefaultImpedanceCutoffs.Clear();
                serviceAreaParameters.DefaultImpedanceCutoffs.Add(0);
                serviceAreaParameters.DefaultImpedanceCutoffs.Add(3);
                serviceAreaParameters.DefaultImpedanceCutoffs.Add(5);

                // A query that finds all of the relevant facilities from the facilities feature service.
                QueryParameters facilityQueryParameters = new QueryParameters();
                facilityQueryParameters.WhereClause = "1=1";

                // Provide the feature service and the query as parameters to the service area task.
                serviceAreaParameters.SetFacilities(_facilitiesTable, facilityQueryParameters);

                // Perform the service area analysis.
                ServiceAreaResult result = await _serviceAreaTask.SolveServiceAreaAsync(serviceAreaParameters);

                // Count the features in the facilities layer. 
                long facilityCount = await _facilitiesTable.QueryFeatureCountAsync(facilityQueryParameters);

                // Get the service area for each facility.
                for (int facilityIndex = 0; facilityIndex < facilityCount; facilityIndex++)
                {
                    // Get each area polygon from the result for that facility.
                    List<ServiceAreaPolygon> areaPolygons = result.GetResultPolygons(facilityIndex).ToList();

                    // Add each service area polygon to the graphics overlay.
                    for (int polygonIndex = 0; polygonIndex < areaPolygons.Count; polygonIndex++)
                    {
                        // Get the polygon from the result.
                        Polygon resultingPolygon = areaPolygons[polygonIndex].Geometry;

                        // Choose a symbol for the polygon.
                        SimpleFillSymbol selectedSymbol = _fillSymbols[polygonIndex % _fillSymbols.Count];

                        // Create and add the graphic.
                        _resultOverlay.Graphics.Add(new Graphic(resultingPolygon, selectedSymbol));
                    }
                }

                // Zoom to the extent of the results.
                await MyMapView.SetViewpointGeometryAsync(_resultOverlay.Extent, 50);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
                ShowMessage("Error", "Couldn't complete service area analysis.");
            }
        }

        private async void FindServiceArea_Clicked(object sender, RoutedEventArgs e)
        {
            try
            {
                // Clear the old results.
                _resultOverlay?.Graphics.Clear();

                // Update the UI.
                ServiceAreaButton.IsEnabled = false;
                ProgressView.Visibility = Visibility.Visible;

                // Do the service area work.
                await FindServiceAreas();

                // Update the UI.
                ProgressView.Visibility = Visibility.Collapsed;
                ServiceAreaButton.IsEnabled = true;
            }
            catch (Exception exception)
            {
                System.Diagnostics.Debug.WriteLine(exception);
                ShowMessage("Error", "Couldn't complete the service area analysis.");
            }
        }

        private void ShowMessage(string title, string detail) => MessageBox.Show(detail, title);
    }
}
XAML
<UserControl
    x:Class="ArcGISRuntime.WPF.Samples.FindServiceAreasForMultipleFacilities.FindServiceAreasForMultipleFacilities"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esri="http://schemas.esri.com/arcgis/runtime/2013">
    <Grid>
        <esri:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <StackPanel>
                <Button
                    x:Name="ServiceAreaButton"
                    Click="FindServiceArea_Clicked"
                    Content="Find service areas"
                    IsEnabled="False" />
                <ProgressBar
                    x:Name="ProgressView"
                    MinHeight="10"
                    IsIndeterminate="True"
                    Visibility="Collapsed" />
            </StackPanel>
        </Border>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
FindPlaceFind places of interest near a location or within a specific area.
FindServiceAreasForMultipleFacilitiesFind the service areas of several facilities from a feature service.