Area and Perimeter Online

This sample demonstrates use of a GeometryService to measure area and perimeter. To use the sample, click subsequent points on the map to draw a polygon. Double-click to complete the polygon. Once the polygon is completed, its area and perimeter will be calculated and displayed in the upper right corner of the application.

In the code-behind, a GeometryService is used to first project the polygon into a spatial reference that uses measured units, and then to calculate the area and perimeter of the polygon.

XAML

<UserControl x:Class="ArcGISWPFSDK.AreasAndLengths"
    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="Transparent">

        <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:SimpleFillSymbol x:Key="DefaultFillSymbol" Fill="#7F0000FF" BorderBrush="Blue" BorderThickness="4" />
        </Grid.Resources>

        <esri:Map x:Name="MyMap">
            <esri:ArcGISTiledMapServiceLayer ID="StreetMapLayer" 
                Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" />
            <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="ResponseTextBlock" Text="Create a polygon by clicking on map. The area and perimeter are displayed here." 
                       Width="200" TextAlignment="Left" Margin="30,20,20,30" TextWrapping="Wrap" Foreground="Black"/>
        </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;

namespace ArcGISWPFSDK
{
    public partial class AreasAndLengths : UserControl
    {
        private Draw MyDrawObject;

        public AreasAndLengths()
        {
            InitializeComponent();
            ESRI.ArcGIS.Client.Geometry.Envelope initialExtent =
                new ESRI.ArcGIS.Client.Geometry.Envelope(
            ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(
                new ESRI.ArcGIS.Client.Geometry.MapPoint(-130, 20)),
            ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(
                new ESRI.ArcGIS.Client.Geometry.MapPoint(-65, 55)));

            initialExtent.SpatialReference = new SpatialReference(102100);

            MyMap.Extent = initialExtent;

            MyDrawObject = new Draw(MyMap)
            {
                DrawMode = DrawMode.Polygon,
                IsEnabled = true,
                FillSymbol = LayoutRoot.Resources["DefaultFillSymbol"] as ESRI.ArcGIS.Client.Symbols.FillSymbol
            };
            MyDrawObject.DrawComplete += MyDrawObject_DrawComplete;
            MyDrawObject.DrawBegin += MyDrawObject_DrawBegin;

        }

        private void MyDrawObject_DrawBegin(object sender, EventArgs args)
        {
            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();
        }

        private void MyDrawObject_DrawComplete(object sender, DrawEventArgs args)
        {
            ESRI.ArcGIS.Client.Geometry.Polygon polygon = args.Geometry as ESRI.ArcGIS.Client.Geometry.Polygon;
            polygon.SpatialReference = MyMap.SpatialReference;
            Graphic graphic = new Graphic()
            {
                Symbol = LayoutRoot.Resources["DefaultFillSymbol"] as ESRI.ArcGIS.Client.Symbols.FillSymbol,
                Geometry = polygon,
            };

            GeometryService geometryService =
                new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
            geometryService.AreasAndLengthsCompleted += GeometryService_AreasAndLengthsCompleted;
            geometryService.Failed += GeometryService_Failed;

            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            graphicsLayer.Graphics.Add(graphic);

            List<Graphic> graphicList = new List<Graphic>();
            graphicList.Add(graphic);

            geometryService.AreasAndLengthsAsync(graphicList);

            // GeometryService.AreasAndLengths returns distances and areas in the units of the spatial reference.
            // The units in the map view's projection is decimal degrees. 
            // Use the Project method to convert graphic points to a projection that uses a measured unit (e.g. meters).
            // If the map units are in measured units, the call to Project is unnecessary. 
            // Important: Use a projection appropriate for your area of interest.
        }

        private void GeometryService_AreasAndLengthsCompleted(object sender, AreasAndLengthsEventArgs args)
        {
            //TODO: Geometry service not returning correct values, area unit seems invalid, may need to use data in 
            //planar coordinate space

            // convert results from meters into miles and sq meters into sq miles for our display
            double miles = args.Results.Lengths[0] * 0.0006213700922;
            double sqmi = Math.Abs(args.Results.Areas[0]) * 0.0000003861003;
            ResponseTextBlock.Text = String.Format("Polygon area: {0} sq. miles\nPolygon perimeter: {1} miles.", Math.Round(sqmi, 3), Math.Round(miles, 3));
        }

        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

Namespace ArcGISWPFSDK
    Partial Public Class AreasAndLengths
        Inherits UserControl
        Private MyDrawObject As Draw

        Public Sub New()
            InitializeComponent()
            Dim initialExtent As New ESRI.ArcGIS.Client.Geometry.Envelope(ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(New ESRI.ArcGIS.Client.Geometry.MapPoint(-130, 20)), ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(New ESRI.ArcGIS.Client.Geometry.MapPoint(-65, 55)))

            initialExtent.SpatialReference = New SpatialReference(102100)

            MyMap.Extent = initialExtent

            MyDrawObject = New Draw(MyMap) With { _
             .DrawMode = DrawMode.Polygon, _
             .IsEnabled = True, _
             .FillSymbol = TryCast(LayoutRoot.Resources("DefaultFillSymbol"), ESRI.ArcGIS.Client.Symbols.FillSymbol) _
            }
            AddHandler MyDrawObject.DrawComplete, AddressOf MyDrawObject_DrawComplete

            AddHandler MyDrawObject.DrawBegin, AddressOf MyDrawObject_DrawBegin
        End Sub

        Private Sub MyDrawObject_DrawBegin(sender As Object, args As EventArgs)
            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            graphicsLayer.ClearGraphics()
        End Sub

        Private Sub MyDrawObject_DrawComplete(sender As Object, args As DrawEventArgs)
            Dim polygon As ESRI.ArcGIS.Client.Geometry.Polygon = TryCast(args.Geometry, ESRI.ArcGIS.Client.Geometry.Polygon)
            polygon.SpatialReference = MyMap.SpatialReference
            Dim graphic As New Graphic() With { _
             .Symbol = TryCast(LayoutRoot.Resources("DefaultFillSymbol"), ESRI.ArcGIS.Client.Symbols.FillSymbol), _
             .Geometry = polygon _
            }

            Dim geometryService As New GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer")
            AddHandler geometryService.AreasAndLengthsCompleted, AddressOf GeometryService_AreasAndLengthsCompleted
            AddHandler geometryService.Failed, AddressOf GeometryService_Failed

            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            graphicsLayer.Graphics.Add(graphic)

            Dim graphicList As New List(Of Graphic)()
            graphicList.Add(graphic)

            geometryService.AreasAndLengthsAsync(graphicList)

            ' GeometryService.AreasAndLengths returns distances and areas in the units of the spatial reference.
            ' The units in the map view's projection is decimal degrees. 
            ' Use the Project method to convert graphic points to a projection that uses a measured unit (e.g. meters).
            ' If the map units are in measured units, the call to Project is unnecessary. 
            ' Important: Use a projection appropriate for your area of interest.
        End Sub

        Private Sub GeometryService_AreasAndLengthsCompleted(sender As Object, args As AreasAndLengthsEventArgs)
            'TODO: Geometry service not returning correct values, area unit seems invalid, may need to use data in 
            'planar coordinate space

            ' convert results from meters into miles and sq meters into sq miles for our display
            Dim miles As Double = args.Results.Lengths(0) * 0.0006213700922
            Dim sqmi As Double = Math.Abs(args.Results.Areas(0)) * 0.0000003861003
            ResponseTextBlock.Text = [String].Format("Polygon area: {0} sq. miles" & vbLf & "Polygon perimeter: {1} miles.", Math.Round(sqmi, 3), Math.Round(miles, 3))
        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