Ranting a bit on the changes in ArcGIS Server 10.1.

ESRI is changing the way the ArcGIS Server works in ArcGIS 10.1, See Considerations for ArcGIS Server developers: A look toward 10.1

We build a lot of SOA webservices leveraging the ArcGIS Server. These are mostly built using the pattern shown here: How to create a geocode and search Web service one of the reasons for building our web services using this pattern, was that the support for Server Object Extensions were poor and still is in ArcGIS 10. You needed to create COM enabled classes that has to be registered on the server etc, no tools, you need to write own tool (Or download SOExplorer) see: SOE Web services


To make the transition easier, I think that ESRI need to give us better tools to handle the SOE, SOAP and REST in ArcGIS Server and in ArcGIS Desktop/Engine. Also provide a solid pattern on how to build enterprise systems where the GIS systems can communicate with other business systems.

Consume ArcGIS Server REST API using WCF.

Have been trying this all day (It does not work), so I write my findings down so it can be continued another day. Found a great blog post here How to consume REST services with WCF that I tried to adapt create a client proxy against ArcGIS Server REST API. The first part creating a Operation contract an adding an endpoint to was easy to do:

 [ServiceContract ]

     public  interface  IArcGISApi 

     {

         //http://help.arcgis.com/en/arcgisserver/10.0/apis/rest/index.html 

         //http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer/1/query?geometry=-125.4,35.2,-118.7,43.8&geometryType=esriGeometryEnvelope  

         [OperationContract ]

         [WebGet (

             BodyStyle = WebMessageBodyStyle .Bare,

             ResponseFormat = WebMessageFormat .Json,

             UriTemplate = "?f=json&Where={query}&returnGeometry=true&returnIdsOnly=false&outFields=*" )]

             //UriTemplate = "?method=flickr.interestingness.getList&api_key={apiKey}&extras={extras}")] 

             QueryResponse  Query(string  query);

     }

The app.config is configured like this:

 <?xml version= "1.0 " encoding= "utf-8 " ?> 

 <configuration> 

   <system.serviceModel> 

     <client> 

       <endpoint address= "http://server.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Median_Household_Income/MapServer/4/query "

                 binding= "webHttpBinding "

                 bindingConfiguration= "ArcGISBinding "

                 behaviorConfiguration= "ArcGIS "

                 contract= "TestRestWCFClient.IArcGISApi "

                 name= "ArcGISREST " /> 

     </client> 

     <bindings> 

       <webHttpBinding> 

         <binding name= "ArcGISBinding " maxReceivedMessageSize= "10000000 "/> 

       </webHttpBinding> 

     </bindings> 

     <behaviors> 

       <endpointBehaviors> 

         <behavior name= "ArcGIS "> 

           <webHttp/> 

         </behavior> 

       </endpointBehaviors> 

     </behaviors> 

   </system.serviceModel> 

   </configuration>

And the code for running sending a query looks like this:

 ChannelFactory <IArcGISApi > factory = new  ChannelFactory <IArcGISApi >("ArcGISREST" );

             var  proxy = factory.CreateChannel();

             var  response = proxy.Query(" );

             ((IDisposable )proxy).Dispose();

What's not working? Well seems like the response is "text/plain" (checked with fiddler) instead of "application/json". I haven't found a way to force it to be sent as "application/json". The error I get is: "The incoming message has an unexpected message format 'Raw'. The expected message formats for the operation are 'Xml'; 'Json'. This can be because a WebContentTypeMapper has not been configured on the binding. See the documentation of WebContentTypeMapper for more details."


Update: To make it work read: http://mathiaswestin.blogspot.com/2011/02/solved-incoming-message-has-unexpected.html

Zoom in to feature in ArcGIS Engine using ArcGIS Server and IFind

The second blog post on how to use ArcGIS Server from ArcGIS Engine. This post show how to zoom in on a feature using a IFind searching for a specific value on an attribute.

Basic steps include getting the layer from the map and casting the layer to the IFind interface and searching the layer for the feature. The project are expecting that the layer href="http://server.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Median_Household_Income/MapServer is loaded in the map.

 Private Sub FindUsingIFindToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles FindUsingIFindToolStripMenuItem.Click
     OnFind()
   End Sub
  
   Private Sub OnFind()
     Dim state As String = "Alaska"
     Dim attribute As String = "Name"
     Dim layername As String = "States"
     Dim control As AxMapControl = axMapControl1
     Dim layer As ILayer = getLayer(layername)
     Dim stateGeometry As IGeometry = Me.Find(layer, attribute, state, control.ActiveView)
     control.ActiveView.Extent = stateGeometry.Envelope
     control.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewAll, Nothing, Nothing)
   End Sub  

The code for getting the layer from the map.

 Private Function getLayer(ByVal name As String) As ILayer
     Dim retLayer As ILayer = Nothing
     Dim control As AxMapControl = axMapControl1
     For i As Integer = 0 To control.Map.LayerCount - 1
       Dim layer As ILayer = control.Map.Layer(i)
       retLayer = Me.getLayer(name, layer)
       If Not retLayer Is Nothing Then
         Exit For
       End If
     Next
     Return retLayer
   End Function
  
   Private Function getLayer(ByVal name As String, ByVal layer As ILayer) As ILayer
     Dim retLayer As ILayer = Nothing
     If TypeOf layer Is ICompositeLayer Then
       Dim gLayer As ICompositeLayer = CType(layer, ICompositeLayer)
       For i As Integer = 0 To gLayer.Count - 1
         Dim l As ILayer = gLayer.Layer(i)
         'söker rekursivt efter lagret
         retLayer = Me.getLayer(name, l)
         If Not retLayer Is Nothing Then
           Exit For
         End If
       Next
     Else
       If layer.Name.Equals(name) Then
         retLayer = layer
       End If
     End If
     Return retLayer
   End Function  

The code that does the actual IFind. We cast the layer to IFind and use the Find method on the interface. Important to note is that it only work when you search for a value on an attribute, you can't do a custom query on serveral attributes.

 Private Function Find(ByVal layer As ILayer, ByVal field As String, ByVal value As String, ByVal activeView As IActiveView) As IGeometry5
     Dim findLayer As IFind = CType(layer, IFind)
     Dim fields As String() = {field}
     'Söker med IFind efter features med attributet satt till value.
     Dim array As IArray = findLayer.Find(value, True, fields, activeView.ScreenDisplay.CancelTracker)
     Dim polygon As IPolygon5 = Nothing
     For i As Integer = 0 To array.Count - 1
       Dim featureFindData As IFeatureFindData2 = CType(array.Element(i), IFeatureFindData2)
       Dim featureFields As IFields = featureFindData.Feature.Fields
       Dim feature As IFeature = featureFindData.Feature
       If (polygon Is Nothing) Then
         polygon = CType(feature.Shape, IPolygon5)
       Else
         Dim topOp As ITopologicalOperator6 = CType(feature.Shape, ITopologicalOperator6)
         polygon = CType(topOp.UnionEx(CType(polygon, IGeometry), True), IPolygon5)
       End If
     Next
     Return CType(polygon, IGeometry5)  
   End Function
  

The same result as I got in the previous blog post, load the layer showing whole US:



And after running the find tool it shows Alaska:

Zoom-in to feature in ArcGIS Engine using ArcGIS Server and REST

The first blog post on how to use ArcGIS Server from ArcGIS Engine. This post show how to zoom in on a feature using a custom query.

I start by creating JSON query:

 Private Sub TestREST2ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TestREST2ToolStripMenuItem.Click
     Dim state As String = "Alaska"
     'Skapar fråga för REST:
     Dim requestUri As String = "http://server.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Median_Household_Income/MapServer/4/query"
     Dim data As New StringBuilder()
     data.AppendFormat("?f={0}", "json")
     'case sensitive
     data.AppendFormat("&Where=Name%3D'" & state & "'")
     data.AppendFormat("&returnGeometry=true")
     data.AppendFormat("&returnIdsOnly=false")
     data.AppendFormat("&outFields=*")
     ZoomTo(requestUri, data.ToString())
   End Sub 

Check out the service http://server.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Median_Household_Income/MapServer/4/query to find out what questions you can ask.

The ZoomTo method looks like this and loops through the result for the features returned and zoom in to the extent of the polygon returned:

 Sub ZoomTo(ByVal requestUri As String, ByVal data As String)
     'Ställer REST frågan:
     Dim request As HttpWebRequest = TryCast(WebRequest.Create(requestUri & data), HttpWebRequest)
     'Hanterar resultat
     Using response As HttpWebResponse = TryCast(request.GetResponse(), HttpWebResponse)
       Dim reader As New StreamReader(response.GetResponseStream())
       Dim responseString As String = reader.ReadToEnd()
       Dim jss As New System.Web.Script.Serialization.JavaScriptSerializer()
       jss.MaxJsonLength = 10000000
       'Skulle kunna köra med datakontrakt, men då måste man skapa objektstrukturen.
       'DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(object))
       'Parsar resultatet för att skapa upp polygon.
       Dim results As IDictionary(Of String, Object) = TryCast(jss.DeserializeObject(responseString), IDictionary(Of String, Object))
       If results IsNot Nothing AndAlso results.ContainsKey("features") Then
         Dim features As IEnumerable(Of Object) = TryCast(results("features"), IEnumerable(Of Object))
         For Each feature As IDictionary(Of String, Object) In features
           Dim geometries As IDictionary(Of String, Object) = TryCast(feature("geometry"), IDictionary(Of String, Object))
           Dim polygon As Polygon = New Polygon()
           Dim rings As IEnumerable(Of Object) = TryCast(geometries("rings"), IEnumerable(Of Object))
           Dim i As Integer = rings.Count()
           For Each ring As IEnumerable(Of Object) In rings
             Dim pointCol As IPointCollection = New Ring()
             For Each vertex As IEnumerable(Of Object) In ring
               Dim point As IPoint = New Point()
               point.X = Convert.ToDouble(vertex.ElementAt(0))
               point.Y = Convert.ToDouble(vertex.ElementAt(1))
               pointCol.AddPoint(point)
             Next
             polygon.AddPointCollection(pointCol)
           Next
           'Sätter om extent via polygonens
           Dim control As AxMapControl = axMapControl1
           control.ActiveView.Extent = TryCast(polygon, IPolygon).Envelope
           control.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewAll, Nothing, Nothing)
           'GetLegend()
           'Dim attributes As IDictionary(Of String, Object) = TryCast(feature("attributes"), IDictionary(Of String, Object))
         Next
       End If
     End Using  
   End Sub  

I'm making a lot of assumptions here, that the result is a polygon, that there is only one polygon returned. But it shows the concept of getting features using REST.



The test application shows US when I start:



And zoom in on Alaska when I run the test method:


I have not done anything to boost the performance, so it feels very slow.