Buffer a Point

This sample demonstrates using the ArcGIS Runtime SDK for WPF to perform a geometry operation to calculate a buffer. To use the sample, simply click a point on the map. The click point and a buffer of 1000km around the point will be shown.

In the code-behind, a LocalGeometryService is started. The url is passed into a GeometryService which is used to buffer the point. Note that, for accurate results, the BufferSpatialReference is set based on the area of interest.

XAML

<UserControl x:Class="ArcGISWPFSDK.LocalBufferPoint"
    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/client/2009">
    <Grid x:Name="LayoutRoot">

        <Grid.Resources>
            <LinearGradientBrush x:Key="PanelGradient" EndPoint="0.5,1" StartPoint="0.5,0">
                <LinearGradientBrush.RelativeTransform>
                    <TransformGroup>
                        <ScaleTransform CenterY="0.5" CenterX="0.5"/>
                        <SkewTransform CenterY="0.5" CenterX="0.5"/>
                        <RotateTransform Angle="176" CenterY="0.5" CenterX="0.5"/>
                        <TranslateTransform/>
                    </TransformGroup>
                </LinearGradientBrush.RelativeTransform>
                <GradientStop Color="#FF145787" Offset="0.16"/>
                <GradientStop Color="#FF3D7FAC" Offset="0.502"/>
                <GradientStop Color="#FF88C5EF" Offset="0.984"/>
            </LinearGradientBrush>
            <esri:PictureMarkerSymbol x:Key="DefaultClickSymbol" OffsetX="11" OffsetY="39" Source="/Assets/Images/i_pushpin.png" />
            <esri:SimpleFillSymbol x:Key="DefaultBufferSymbol" Fill="#660000FF" BorderBrush="Blue" BorderThickness="2"  />
        </Grid.Resources>

        <esri:Map x:Name="MyMap" MouseClick="MyMap_MouseClick" Extent="-15000000,2000000,-7000000,8000000" Background="#FFE3E3E3" IsEnabled="False">
            <esri:ArcGISLocalTiledLayer ID="BaseMap" Path="..\\Data\\TPKs\\Topographic.tpk"/>
            <esri:GraphicsLayer ID="MyGraphicsLayer" />
        </esri:Map>

        <Grid HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,10,10,0" >
            <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray"  RadiusX="10" RadiusY="10" Margin="0,0,0,5" >
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#FFFFFFFF" Stroke="DarkGray" RadiusX="5" RadiusY="5" Margin="10,10,10,15" />
            <TextBlock x:Name="InformationTextBlock" Text="Click on map to set a location. A buffer of 5 degrees will be displayed." 
                       Width="200" TextAlignment="Left" Margin="30,20,25,30" TextWrapping="Wrap" Foreground="Black" />
        </Grid>

    </Grid>
</UserControl>

C#

using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Geometry;
using ESRI.ArcGIS.Client.Tasks;
using ESRI.ArcGIS.Client.Local;

namespace ArcGISWPFSDK
{
    public partial class LocalBufferPoint : UserControl
    {
        GeometryService _geometryTask;

        public LocalBufferPoint()
        {
            InitializeComponent();
 
            LocalGeometryService.GetServiceAsync(localGeometryService => 
            {                
                _geometryTask = new GeometryService();
                _geometryTask.Url = localGeometryService.UrlGeometryService;
                _geometryTask.BufferCompleted += GeometryService_BufferCompleted;
                _geometryTask.Failed += GeometryService_Failed;
                MyMap.IsEnabled = true;

            });
        }

        private void MyMap_MouseClick(object sender, ESRI.ArcGIS.Client.Map.MouseEventArgs e)
        {
            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();

            e.MapPoint.SpatialReference = MyMap.SpatialReference;
            Graphic graphic = new ESRI.ArcGIS.Client.Graphic()
            {
                Geometry = e.MapPoint,
                Symbol = LayoutRoot.Resources["DefaultClickSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol
            };
            graphic.SetZIndex(1);
            graphicsLayer.Graphics.Add(graphic);

            BufferParameters bufferParams = new BufferParameters()
            {
                Unit = LinearUnit.Degree,
                BufferSpatialReference = new SpatialReference(4326),
                OutSpatialReference = MyMap.SpatialReference
            };
            bufferParams.Features.Add(graphic);
            bufferParams.Distances.Add(5);

            _geometryTask.BufferAsync(bufferParams);
        }

        void GeometryService_BufferCompleted(object sender, GraphicsEventArgs args)
        {
            IList<Graphic> results = args.Results;
            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

            foreach (Graphic graphic in results)
            {
                graphic.Symbol = LayoutRoot.Resources["DefaultBufferSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
                graphicsLayer.Graphics.Add(graphic);
            }
        }

        private void GeometryService_Failed(object sender, TaskFailedEventArgs e)
        {
            MessageBox.Show("Geometry Service error: " + e.Error);
        }
    }
}

VB.NET

Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Controls
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Geometry
Imports ESRI.ArcGIS.Client.Tasks
Imports ESRI.ArcGIS.Client.Local

Namespace ArcGISWPFSDK
    Partial Public Class LocalBufferPoint
        Inherits UserControl
        Private geometryService As GeometryService
        Public Sub New()
            InitializeComponent()
            Dim localGeometryService As New LocalGeometryService()

            AddHandler localGeometryService.StartCompleted, Function(sender, eventargs)
                                                                Dim lgs As LocalGeometryService = TryCast(sender, LocalGeometryService)

                                                                geometryService = New GeometryService()
                                                                geometryService.Url = lgs.UrlGeometryService
                                                                AddHandler geometryService.BufferCompleted, AddressOf GeometryService_BufferCompleted
                                                                AddHandler geometryService.Failed, AddressOf GeometryService_Failed

                                                                MyMap.IsEnabled = True

                                                            End Function
            localGeometryService.StartAsync()
        End Sub

        Private Sub MyMap_MouseClick(sender As Object, e As ESRI.ArcGIS.Client.Map.MouseEventArgs)
            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            graphicsLayer.ClearGraphics()

            e.MapPoint.SpatialReference = MyMap.SpatialReference
            Dim graphic As Graphic = New ESRI.ArcGIS.Client.Graphic() With { _
             .Geometry = e.MapPoint, _
             .Symbol = TryCast(LayoutRoot.Resources("DefaultClickSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol) _
            }
            graphic.SetZIndex(1)
            graphicsLayer.Graphics.Add(graphic)

            Dim bufferParams As New BufferParameters() With { _
             .Unit = LinearUnit.Degree, _
             .BufferSpatialReference = New SpatialReference(4326), _
             .OutSpatialReference = MyMap.SpatialReference _
            }
            bufferParams.Features.Add(graphic)
            bufferParams.Distances.Add(5)

            geometryService.BufferAsync(bufferParams)
        End Sub

        Private Sub GeometryService_BufferCompleted(sender As Object, args As GraphicsEventArgs)
            Dim results As IList(Of Graphic) = args.Results
            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)

            For Each graphic As Graphic In results
                graphic.Symbol = TryCast(LayoutRoot.Resources("DefaultBufferSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
                graphicsLayer.Graphics.Add(graphic)
            Next
        End Sub

        Private Sub GeometryService_Failed(sender As Object, e As TaskFailedEventArgs)
            MessageBox.Show("Geometry Service error: " & Convert.ToString(e.[Error]))
        End Sub
    End Class
End Namespace