SOE Elevation Data Online

This sample demonstrates how to use a custom Server Object Extension (SOE) hosted by ArcGIS for Server. The SOE operation used in this example returns a set of interpolated elevation values for a user defined grid. The grid extent and number of rows and columns are provided as inputs. More information on SOEs can be found here: http://resources.arcgis.com/en/help/main/10.1/index.html#/What_is_a_server_object_extension/0154000004s5000000/. The SOE is accessible via the ArcGIS for Server REST API. A web request is programmatically constructed by populating argument\value pairs to match parameters defined by the SOE's REST schema (discoverable via the ArcGIS for Server REST Services Directory). The response from the SOE contains string data in JSON (JavaScript Object Notation) format. There are a variety of techniques for handling JSON in WPF. This sample uses the DataContractJsonSerializer Class to deserialize the JSON response from the server. For more information on the DataContractJsonSerializer see http://msdn.microsoft.com/en-GB/library/system.runtime.serialization.json.datacontractjsonserializer(v=vs.100).aspx. The types to which the JSON is deserialized can be automatically created based on the URL or the returned JSON by using a service such as Json2CSharp (http://json2csharp.com/). Alternatively you can use the JavaScriptSerializer (http://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer(v=vs.100).aspx) or there are a number of 3rd party JSON libraries available such as Json.NET (http://james.newtonking.com/projects/json-net.aspx).

XAML

<UserControl x:Class="ArcGISWPFSDK.SOEElevationData"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
	xmlns:esri="http://schemas.esri.com/arcgis/client/2009">

    <Grid x:Name="LayoutRoot">
        <Grid.Resources>
            <esri:SimpleFillSymbol x:Key="DrawFillSymbol" Fill="#33FF0000" BorderBrush="Red" BorderThickness="1" />
        </Grid.Resources>

        <esri:Map x:Name="MyMap" UseAcceleratedDisplay="True">
            <esri:ArcGISTiledMapServiceLayer 
                Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer" />
            <esri:GraphicsLayer ID="MyGraphicsLayer"/>
        </esri:Map>

        <Grid HorizontalAlignment="Left" VerticalAlignment="Top" Margin="10,10,0,0" >
            <Rectangle Fill="#77919191" Stroke="Gray"  Margin="0,0,0,5" >
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#FFFFFFFF" Stroke="DarkGray" Margin="10,10,10,15" />
            <StackPanel Orientation="Vertical" Margin="30,20,20,30" >
                <TextBlock Text="Enter width and height (in pixels) of a grid overlay and drag a box on the map to define grid extent.  A bitmap of average elevation values will be displayed in a separate panel." 
                           Width="200" TextAlignment="Left"  TextWrapping="Wrap" Margin="0,0,0,5"/>
                <StackPanel Orientation="Horizontal" Margin="3">
                    <TextBlock Text="Width:" VerticalAlignment="Center" Margin="3"   />
                    <TextBox x:Name="WidthTextBox" Text="15" Width="26" />
                    <TextBlock Text="Height:" Margin="9,3,3,3" VerticalAlignment="Center"  />
                    <TextBox x:Name="HeightTextBox"  Text="15" Width="26" />                
                </StackPanel>
            </StackPanel>
        </Grid>

        <Grid x:Name="ElevationView" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,10,10,0" Visibility="Collapsed" >
            <Rectangle Fill="#77919191" Stroke="Gray"  Margin="0,0,0,5" >
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#FFFFFFFF" Stroke="DarkGray" Margin="10,18,10,15" />
            <StackPanel HorizontalAlignment="Right" Orientation="Horizontal" VerticalAlignment="Top" Margin="0,2,8,0" >
                <Rectangle x:Name="SizeProfileImage" Stroke="Black" Fill="#00FFFFFF" Width="8" Height="4" Margin="0,0,5,0" 
                           MouseLeftButtonDown="SizeProfileImage_MouseLeftButtonDown" ToolTipService.ToolTip="Resize Image" 
                           Cursor="Hand"  />
                <TextBlock x:Name="CloseProfileImage" Foreground="Black" Text="X" 
                           MouseLeftButtonDown="CloseProfileImage_MouseLeftButtonDown" Cursor="Hand" 
                           ToolTipService.ToolTip="Close" />
            </StackPanel>
            <TextBlock Text="Elevation Grid" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="15,2,0,0" 
                       FontWeight="Bold"  />
            <Image x:Name="ElevationImage" Width="150" Height="150" Stretch="Fill" Margin="20,30,20,25" />
        </Grid>

    </Grid>
</UserControl>

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using ESRI.ArcGIS.Client;
using System.Windows.Media.Imaging;
using ESRI.ArcGIS.Client.Symbols;
using System.Runtime.Serialization.Json;
using ESRI.ArcGIS.Client.Geometry;

namespace ArcGISWPFSDK
{
    public partial class SOEElevationData : UserControl
    {
        Draw myDrawObject;
        WebClient webClient;
        GraphicsLayer graphicsLayer;
        List<Color> colorRanges = new List<Color>(); 

        public SOEElevationData()
        {
            InitializeComponent();
            myDrawObject = new Draw(MyMap)
            {
                DrawMode = DrawMode.Rectangle,
                FillSymbol = LayoutRoot.Resources["DrawFillSymbol"] as ESRI.ArcGIS.Client.Symbols.FillSymbol,
                IsEnabled = true
            };
            myDrawObject.DrawComplete += drawObject_DrawComplete;
            myDrawObject.DrawBegin += drawObject_OnDrawBegin;

            webClient = new WebClient();
            webClient.OpenReadCompleted += wc_OpenReadCompleted;

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

            colorRanges.Add(Colors.Blue);
            colorRanges.Add(Colors.Green);
            colorRanges.Add(Colors.Yellow);
            colorRanges.Add(Colors.Orange);
            colorRanges.Add(Colors.Red);
        }

        private void drawObject_OnDrawBegin(object sender, EventArgs args)
        {
            graphicsLayer.Graphics.Clear();
            ElevationView.Visibility = Visibility.Collapsed;
        }

        void drawObject_DrawComplete(object sender, DrawEventArgs e)
        {
            myDrawObject.IsEnabled = false;

            if (e.Geometry.Extent.Height == 0 | e.Geometry.Extent.Width == 0)
            {
                MessageBox.Show("Please click and drag a box to define an extent.", "Error", MessageBoxButton.OK, MessageBoxImage.Information);
                myDrawObject.IsEnabled = true;
                return;
            }

            ESRI.ArcGIS.Client.Graphic graphic = new ESRI.ArcGIS.Client.Graphic()
            {
                Geometry = e.Geometry,
                Symbol = LayoutRoot.Resources["DrawFillSymbol"] as Symbol
            };
            graphicsLayer.Graphics.Add(graphic);

            ESRI.ArcGIS.Client.Geometry.Envelope aoiEnvelope = e.Geometry as ESRI.ArcGIS.Client.Geometry.Envelope;

            string SOEurl = "http://sampleserver4.arcgisonline.com/ArcGIS/rest/services/Elevation/ESRI_Elevation_World/MapServer/exts/ElevationsSOE/ElevationLayers/1/GetElevationData?";

            SOEurl += string.Format(System.Globalization.CultureInfo.InvariantCulture, "Extent={{\"xmin\" : {0}, \"ymin\" : {1}, \"xmax\" : {2}, \"ymax\" :{3},\"spatialReference\" : {{\"wkid\" : {4}}}}}&Rows={5}&Columns={6}&f=json",
                aoiEnvelope.XMin, aoiEnvelope.YMin, aoiEnvelope.XMax, aoiEnvelope.YMax,
                MyMap.SpatialReference.WKID, HeightTextBox.Text, WidthTextBox.Text);

            /* 
             * e.g. 
             * http://sampleserver4.arcgisonline.com/ArcGIS/rest/services/Elevation/ESRI_Elevation_World/MapServer/exts/ElevationsSOE/ElevationLayers/1/GetElevationData?
             * Extent={"xmin" : -1507310.85889877, "ymin" : 6406071.15031974, "xmax" : 879264.66769094, "ymax" :8164600.48570163,"spatialReference" : {"wkid" : 102100}}&Rows=15&Columns=15&f=json
            */
            
            webClient.OpenReadAsync(new Uri(SOEurl));
        }

        void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
        {
            DataContractJsonSerializer serializer = null;
            ElevationData elevationData = null;

            try
            {
                serializer = new DataContractJsonSerializer(typeof(ElevationData));
                elevationData = serializer.ReadObject(e.Result) as ElevationData;               
            }
            catch (Exception ex)
            {
                // Check for a service error.
                try
                {
                    serializer = new DataContractJsonSerializer(typeof(ServiceError));
                    ServiceError serviceError = serializer.ReadObject(e.Result) as ServiceError;

                    // e.g. {"error":{"code":400,"message":"Value cannot be null.\r\nParameter name: Rows"}}
                    MessageBox.Show(string.Format("Error: {0} meters", serviceError.error.message));
                    myDrawObject.IsEnabled = true;
                    return; 
                }
                catch
                {
                    myDrawObject.IsEnabled = true;
                    MessageBox.Show("Error");
                }
            }

            int thematicMin, thematicMax;

            if (elevationData.data == null)
            {
                MessageBox.Show("Error. Please try again.");
                myDrawObject.IsEnabled = true;
                return;
            }

            thematicMin = thematicMax = elevationData.data[0];

            foreach (int elevValue in elevationData.data)
            {
                if (elevValue < thematicMin) thematicMin = elevValue;
                if (elevValue > thematicMax) thematicMax = elevValue;
            }

            int totalRange = thematicMax - thematicMin;
            int portion = totalRange / 5;

            List<Color> cellColor = new List<Color>();

            foreach (int elevValue in elevationData.data)
            {
                int startValue = thematicMin;
                for (int i = 0; i < 5; i++)
                {
                    if (Enumerable.Range(startValue, portion).Contains(elevValue))
                    {
                        cellColor.Add(colorRanges[i]);
                        break;
                    }
                    else if (i == 4)
                        cellColor.Add(colorRanges.Last());

                    startValue = startValue + portion;
                }
            }

            int rows = Convert.ToInt32(HeightTextBox.Text);
            int cols = Convert.ToInt32(WidthTextBox.Text);
            WriteableBitmap writeableBitmapElevation = new WriteableBitmap(elevationData.nRows, elevationData.nCols, 96, 96, PixelFormats.Bgr32, null);

            int cell = 0;

            for (int x = 0; x < rows; x++)
            {
                for (int y = 0; y < cols; y++)
                {
                    SetPixel(writeableBitmapElevation, x, y, 255, cellColor[cell].R, cellColor[cell].G, cellColor[cell].B);
                    cell++;
                }
            }

            ElevationView.Visibility = System.Windows.Visibility.Visible;
            ElevationImage.Source = writeableBitmapElevation;
            myDrawObject.IsEnabled = true;
        
        }

        void SetPixel(WriteableBitmap bitmap, int row, int col, int alpha, int red, int green, int blue)
        {
            int index = row * bitmap.PixelWidth + col;
            int w = bitmap.PixelWidth;
            int h = bitmap.PixelHeight;
            int[] pixelData = new int[w * h];
            int widthInBytes = 4 * w;
            bitmap.CopyPixels(pixelData, widthInBytes, 0);
            pixelData[index] = (alpha << 24) | (red << 16) | (green << 8) | blue;
            bitmap.WritePixels(new Int32Rect(0, 0, w, h), pixelData, widthInBytes, 0);   
        }

        private void CloseProfileImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            ElevationView.Visibility = Visibility.Collapsed;
        }

        private void SizeProfileImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (ElevationImage.Width == 150)
                ElevationImage.Width = ElevationImage.Height = 300;
            else
                ElevationImage.Width = ElevationImage.Height = 150;
        }
    }

    // Classes for serialization in the case of elevation data 
    public class RasterProperties
    {
        public bool IsInteger { get; set; }
        public int datasetMin { get; set; }
        public int datasetMax { get; set; }
    }

    public class ElevationData 
    {
        public int nCols { get; set; }
        public int nRows { get; set; }
        public double xLLCenter { get; set; }
        public double yLLCenter { get; set; }
        public double cellSize { get; set; }
        public List<int> noDataValue { get; set; }
        public SpatialReference spatialReference { get; set; }
        public List<int> data { get; set; }
        public RasterProperties rasterProperties { get; set; }
    }

    // Classes for serialization in the case of a service error
    public class Error
    {
    public int code { get; set; }
    public string message { get; set; }
    }

    public class ServiceError
    {
        public Error error { get; set; }
    }
}

VB.NET

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Net
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Symbols
Imports System.Runtime.Serialization.Json
Imports ESRI.ArcGIS.Client.Geometry

Namespace ArcGISWPFSDK

    Partial Public Class SOEElevationData
        Inherits UserControl
        Private myDrawObject As Draw
        Private webClient As WebClient
        Private graphicsLayer As GraphicsLayer
        Private colorRanges As New List(Of Color)()

        Public Sub New()
            InitializeComponent()
            myDrawObject = New Draw(MyMap) With {.DrawMode = DrawMode.Rectangle, .FillSymbol = TryCast(LayoutRoot.Resources("DrawFillSymbol"), ESRI.ArcGIS.Client.Symbols.FillSymbol), .IsEnabled = True}
            AddHandler myDrawObject.DrawComplete, AddressOf drawObject_DrawComplete
            AddHandler myDrawObject.DrawBegin, AddressOf drawObject_OnDrawBegin

            webClient = New WebClient()
            AddHandler webClient.OpenReadCompleted, AddressOf wc_OpenReadCompleted

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

            colorRanges.Add(Colors.Blue)
            colorRanges.Add(Colors.Green)
            colorRanges.Add(Colors.Yellow)
            colorRanges.Add(Colors.Orange)
            colorRanges.Add(Colors.Red)
        End Sub

        Private Sub drawObject_OnDrawBegin(ByVal sender As Object, ByVal args As EventArgs)
            graphicsLayer.Graphics.Clear()
            ElevationView.Visibility = Visibility.Collapsed
        End Sub

        Private Sub drawObject_DrawComplete(ByVal sender As Object, ByVal e As DrawEventArgs)
            myDrawObject.IsEnabled = False

            Dim graphic As New ESRI.ArcGIS.Client.Graphic() With {.Geometry = e.Geometry, .Symbol = TryCast(LayoutRoot.Resources("DrawFillSymbol"), Symbol)}
            graphicsLayer.Graphics.Add(graphic)

            Dim aoiEnvelope As ESRI.ArcGIS.Client.Geometry.Envelope = TryCast(e.Geometry, ESRI.ArcGIS.Client.Geometry.Envelope)

            Dim SOEurl As String = "http://sampleserver4.arcgisonline.com/ArcGIS/rest/services/Elevation/ESRI_Elevation_World/MapServer/exts/ElevationsSOE/ElevationLayers/1/GetElevationData?"

            SOEurl &= String.Format(System.Globalization.CultureInfo.InvariantCulture, "Extent={{""xmin"" : {0}, ""ymin"" : {1}, ""xmax"" : {2}, ""ymax"" :{3},""spatialReference"" : {{""wkid"" : {4}}}}}&Rows={5}&Columns={6}&f=json", aoiEnvelope.XMin, aoiEnvelope.YMin, aoiEnvelope.XMax, aoiEnvelope.YMax, MyMap.SpatialReference.WKID, HeightTextBox.Text, WidthTextBox.Text)

            webClient.OpenReadAsync(New Uri(SOEurl))
        End Sub

        Private Sub wc_OpenReadCompleted(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)

            Dim serializer As DataContractJsonSerializer = Nothing
            Dim elevationData As ElevationData = Nothing

            Try
                serializer = New DataContractJsonSerializer(GetType(ElevationData))
                elevationData = TryCast(serializer.ReadObject(e.Result), ElevationData)
            Catch ex As Exception
                serializer = New DataContractJsonSerializer(GetType(ServiceError))
                Dim serviceError As ServiceError = TryCast(serializer.ReadObject(e.Result), ServiceError)

                ' e.g. {"error":{"code":400,"message":"Value cannot be null.\r\nParameter name: Rows"}}
                MessageBox.Show(String.Format("Error: {0} meters", serviceError.[error].message))
                myDrawObject.IsEnabled = True
                Return
            End Try

            'Dim elevData As JsonArray = CType(jsonObjectData("data"), JsonArray)

            Dim thematicMin, thematicMax As Integer
            thematicMax = elevationData.data(0)
            thematicMin = thematicMax

            For Each elevValue As Integer In elevationData.data
                If elevValue < thematicMin Then
                    thematicMin = elevValue
                End If
                If elevValue > thematicMax Then
                    thematicMax = elevValue
                End If
            Next elevValue

            Dim totalRange As Integer = thematicMax - thematicMin
            Dim portion As Integer = totalRange \ 5

            Dim cellColor As New List(Of Color)()

            For Each elevValue As Integer In elevationData.data
                Dim startValue As Integer = thematicMin
                For i As Integer = 0 To 4
                    If Enumerable.Range(startValue, portion).Contains(elevValue) Then
                        cellColor.Add(colorRanges(i))
                        Exit For
                    ElseIf i = 4 Then
                        cellColor.Add(colorRanges.Last())
                    End If

                    startValue = startValue + portion
                Next i
            Next elevValue

            Dim rows As Integer = Convert.ToInt32(HeightTextBox.Text)
            Dim cols As Integer = Convert.ToInt32(WidthTextBox.Text)
            Dim writeableBitmapElevation As New WriteableBitmap(elevationData.nRows, elevationData.nCols, 96, 96, PixelFormats.Bgr32, Nothing)

            Dim cell As Integer = 0

            For x As Integer = 0 To rows - 1
                For y As Integer = 0 To cols - 1
                    SetPixel(writeableBitmapElevation, x, y, 255, cellColor(cell).R, cellColor(cell).G, cellColor(cell).B)
                    cell += 1
                Next y
            Next x

            ElevationView.Visibility = System.Windows.Visibility.Visible
            ElevationImage.Source = writeableBitmapElevation
            myDrawObject.IsEnabled = True
        End Sub

        Private Sub SetPixel(bitmap As WriteableBitmap, row As Integer, col As Integer, alpha As Integer, red As Integer, green As Integer, blue As Integer)
            Dim index As Integer = row * bitmap.PixelWidth + col
            Dim w As Integer = bitmap.PixelWidth
            Dim h As Integer = bitmap.PixelHeight
            Dim pixelData As Integer() = New Integer(w * h - 1) {}
            Dim widthInBytes As Integer = 4 * w
            bitmap.CopyPixels(pixelData, widthInBytes, 0)
            pixelData(index) = (alpha << 24) Or (red << 16) Or (green << 8) Or blue
            bitmap.WritePixels(New Int32Rect(0, 0, w, h), pixelData, widthInBytes, 0)
        End Sub

        Private Sub CloseProfileImage_MouseLeftButtonDown(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
            ElevationView.Visibility = Visibility.Collapsed
        End Sub

        Private Sub SizeProfileImage_MouseLeftButtonDown(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
            If ElevationImage.Width = 150 Then
                ElevationImage.Height = 300
                ElevationImage.Width = ElevationImage.Height
            Else
                ElevationImage.Height = 150
                ElevationImage.Width = ElevationImage.Height
            End If
        End Sub
    End Class

    Public Class RasterProperties
        Public Property IsInteger() As Boolean
            Get
                Return m_IsInteger
            End Get
            Set(value As Boolean)
                m_IsInteger = value
            End Set
        End Property
        Private m_IsInteger As Boolean
        Public Property datasetMin() As Integer
            Get
                Return m_datasetMin
            End Get
            Set(value As Integer)
                m_datasetMin = value
            End Set
        End Property
        Private m_datasetMin As Integer
        Public Property datasetMax() As Integer
            Get
                Return m_datasetMax
            End Get
            Set(value As Integer)
                m_datasetMax = value
            End Set
        End Property
        Private m_datasetMax As Integer
    End Class

    Public Class ElevationData
        Public Property nCols() As Integer
            Get
                Return m_nCols
            End Get
            Set(value As Integer)
                m_nCols = value
            End Set
        End Property
        Private m_nCols As Integer
        Public Property nRows() As Integer
            Get
                Return m_nRows
            End Get
            Set(value As Integer)
                m_nRows = value
            End Set
        End Property
        Private m_nRows As Integer
        Public Property xLLCenter() As Double
            Get
                Return m_xLLCenter
            End Get
            Set(value As Double)
                m_xLLCenter = value
            End Set
        End Property
        Private m_xLLCenter As Double
        Public Property yLLCenter() As Double
            Get
                Return m_yLLCenter
            End Get
            Set(value As Double)
                m_yLLCenter = value
            End Set
        End Property
        Private m_yLLCenter As Double
        Public Property cellSize() As Double
            Get
                Return m_cellSize
            End Get
            Set(value As Double)
                m_cellSize = value
            End Set
        End Property
        Private m_cellSize As Double
        Public Property noDataValue() As List(Of Integer)
            Get
                Return m_noDataValue
            End Get
            Set(value As List(Of Integer))
                m_noDataValue = value
            End Set
        End Property
        Private m_noDataValue As List(Of Integer)
        Public Property spatialReference() As SpatialReference
            Get
                Return m_spatialReference
            End Get
            Set(value As SpatialReference)
                m_spatialReference = value
            End Set
        End Property
        Private m_spatialReference As SpatialReference
        Public Property data() As List(Of Integer)
            Get
                Return m_data
            End Get
            Set(value As List(Of Integer))
                m_data = value
            End Set
        End Property
        Private m_data As List(Of Integer)
        Public Property rasterProperties() As RasterProperties
            Get
                Return m_rasterProperties
            End Get
            Set(value As RasterProperties)
                m_rasterProperties = value
            End Set
        End Property
        Private m_rasterProperties As RasterProperties
    End Class

    Public Class [Error]
        Public Property code() As Integer
            Get
                Return m_code
            End Get
            Set(value As Integer)
                m_code = value
            End Set
        End Property
        Private m_code As Integer
        Public Property message() As String
            Get
                Return m_message
            End Get
            Set(value As String)
                m_message = value
            End Set
        End Property
        Private m_message As String
    End Class

    Public Class ServiceError
        Public Property [error]() As [Error]
            Get
                Return m_error
            End Get
            Set(value As [Error])
                m_error = value
            End Set
        End Property
        Private m_error As [Error]
    End Class
End Namespace