Calculate Viewshed Online

This sample demonstrates use of the Geoprocessor to call a ViewShed geoprocessing service. To use the sample, specify a distance and click a point on the map. Once the viewshed is calculated, it will be shown on the map.

In the code-behind, a Geoprocessor is used to pass the distance and click point to the ViewShed service. When the results are returned, they are added to a GraphicsLayer and shown in the map.

XAML

<UserControl x:Class="ArcGISWPFSDK.ViewShed"
    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" Background="White">

        <Grid.Resources>
            <esri:PictureMarkerSymbol x:Key="StartMarkerSymbol" OffsetX="8" OffsetY="8" 
                 Source="/Assets/Images/i_about.png" />
            <esri:SimpleFillSymbol x:Key="DefaultFillSymbol" Fill="#99FF9999" BorderBrush="#FFFF9999" BorderThickness="2"  />
            <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>
        </Grid.Resources>

        <esri:Map x:Name="MyMap" MouseClick="MyMap_MouseClick" Cursor="Hand" Extent="76.35,35.65,76.65,35.95" >
            <esri:ArcGISTiledMapServiceLayer ID="TopoMapLayer" 
                      Url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
            <esri:GraphicsLayer ID="MyGraphicsLayer" />
        </esri:Map>

        <Grid HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,15,15,0" >
            <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray"  RadiusX="10" RadiusY="10" Margin="0,0,0,5">
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#DDFFFFFF" Stroke="DarkGray" RadiusX="5" RadiusY="5" Margin="10,10,10,15" />
            <StackPanel Orientation="Vertical" Margin="20,20,20,20" HorizontalAlignment="Left" >
                <TextBlock Text="Calculate Viewshed" HorizontalAlignment="Center" FontWeight="Bold" Foreground="Black"/>
                <TextBlock x:Name="InformationTextBlock" Text="Click on map to see the calculated viewshed. Set distance below." 
                            Width="220" TextAlignment="Left" TextWrapping="Wrap" Foreground="Black" />
                <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5,5,5,10">
                    <TextBlock Text="Miles: " VerticalAlignment="Center" Foreground="Black"/>
                    <TextBox x:Name="MilesTextBox" Text="10" Width="35" TextAlignment="Right" Margin="0,0,5,0" />
                </StackPanel>
            </StackPanel>
        </Grid>

    </Grid>
</UserControl>

C#

using System;
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.Symbols;

namespace ArcGISWPFSDK
{
    public partial class ViewShed : UserControl
    {
        Geoprocessor _geoprocessorTask;

        public ViewShed()
        {
            InitializeComponent();
            _geoprocessorTask = new Geoprocessor("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/" +
                "Elevation/ESRI_Elevation_World/GPServer/Viewshed");
            _geoprocessorTask.ExecuteCompleted += GeoprocessorTask_ExecuteCompleted;
            _geoprocessorTask.Failed += GeoprocessorTask_Failed;
        }

        private void MyMap_MouseClick(object sender, ESRI.ArcGIS.Client.Map.MouseEventArgs e)
        {
            _geoprocessorTask.CancelAsync();

            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();

            MapPoint mapPoint = e.MapPoint;
            mapPoint.SpatialReference = new SpatialReference(4326);

            Graphic graphic = new Graphic()
            {
                Symbol = LayoutRoot.Resources["StartMarkerSymbol"] as Symbol,
                Geometry = mapPoint
            };
            graphicsLayer.Graphics.Add(graphic);

            MyMap.Cursor = System.Windows.Input.Cursors.Wait;

            List<GPParameter> parameters = new List<GPParameter>();
            parameters.Add(new GPFeatureRecordSetLayer("Input_Observation_Point", mapPoint));
            parameters.Add(new GPLinearUnit("Viewshed_Distance", esriUnits.esriMiles, Convert.ToDouble(MilesTextBox.Text)));

            _geoprocessorTask.OutputSpatialReference = new SpatialReference(4326);
            _geoprocessorTask.ExecuteAsync(parameters);
        }

        private void GeoprocessorTask_ExecuteCompleted(object sender, ESRI.ArcGIS.Client.Tasks.GPExecuteCompleteEventArgs args)
        {
            MyMap.Cursor = System.Windows.Input.Cursors.Hand;
            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

            foreach (GPParameter gpParameter in args.Results.OutParameters)
            {
                if (gpParameter is GPFeatureRecordSetLayer)
                {
                    GPFeatureRecordSetLayer layer = gpParameter as GPFeatureRecordSetLayer;
                    foreach (Graphic graphic in layer.FeatureSet.Features)
                    {
                        graphic.Symbol = LayoutRoot.Resources["DefaultFillSymbol"] as Symbol;
                        graphicsLayer.Graphics.Add(graphic);
                    }
                }
            }
        }

        private void GeoprocessorTask_Failed(object sender, TaskFailedEventArgs e)
        {
            MyMap.Cursor = System.Windows.Input.Cursors.Hand;
            MessageBox.Show("Geoprocessor service failed: " + 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.Symbols

Namespace ArcGISWPFSDK
    Partial Public Class ViewShed
        Inherits UserControl
        Private _geoprocessorTask As Geoprocessor

        Public Sub New()
            InitializeComponent()
            _geoprocessorTask = New Geoprocessor("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/" & "Elevation/ESRI_Elevation_World/GPServer/Viewshed")
            AddHandler _geoprocessorTask.ExecuteCompleted, AddressOf GeoprocessorTask_ExecuteCompleted
            AddHandler _geoprocessorTask.Failed, AddressOf GeoprocessorTask_Failed
        End Sub

        Private Sub MyMap_MouseClick(sender As Object, e As ESRI.ArcGIS.Client.Map.MouseEventArgs)
            _geoprocessorTask.CancelAsync()

            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            graphicsLayer.ClearGraphics()

            Dim mapPoint As MapPoint = e.MapPoint
            mapPoint.SpatialReference = New SpatialReference(4326)

            Dim graphic As New Graphic() With { _
             .Symbol = TryCast(LayoutRoot.Resources("StartMarkerSymbol"), Symbol), _
             .Geometry = mapPoint _
            }
            graphicsLayer.Graphics.Add(graphic)

            MyMap.Cursor = System.Windows.Input.Cursors.Wait

            Dim parameters As New List(Of GPParameter)()
            parameters.Add(New GPFeatureRecordSetLayer("Input_Observation_Point", mapPoint))
            parameters.Add(New GPLinearUnit("Viewshed_Distance", esriUnits.esriMiles, Convert.ToDouble(MilesTextBox.Text)))

            _geoprocessorTask.OutputSpatialReference = New SpatialReference(4326)
            _geoprocessorTask.ExecuteAsync(parameters)
        End Sub

        Private Sub GeoprocessorTask_ExecuteCompleted(sender As Object, args As ESRI.ArcGIS.Client.Tasks.GPExecuteCompleteEventArgs)
            MyMap.Cursor = System.Windows.Input.Cursors.Hand
            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)

            For Each gpParameter As GPParameter In args.Results.OutParameters
                If TypeOf gpParameter Is GPFeatureRecordSetLayer Then
                    Dim layer As GPFeatureRecordSetLayer = TryCast(gpParameter, GPFeatureRecordSetLayer)
                    For Each graphic As Graphic In layer.FeatureSet.Features
                        graphic.Symbol = TryCast(LayoutRoot.Resources("DefaultFillSymbol"), Symbol)
                        graphicsLayer.Graphics.Add(graphic)
                    Next
                End If
            Next
        End Sub

        Private Sub GeoprocessorTask_Failed(sender As Object, e As TaskFailedEventArgs)
            MyMap.Cursor = System.Windows.Input.Cursors.Hand
            MessageBox.Show("Geoprocessor service failed: " & Convert.ToString(e.[Error]))
        End Sub
    End Class
End Namespace