title: Intersect two layers and get resulting features
body: <p>I have X layers on a map and I need to intersect chosen layers (two per time) and color resulting features.</p>
  
  <p>I'm trying to get this code working</p>
  
  <pre><code>// get first feature (index 0)
  ESRI.ArcGIS.ADF.Web.Geometry.Geometry adfFeature =
                  m_firstLayer.GeometryFromRow(m_firstLayer.Rows[0]) 
  as ESRI.ArcGIS.ADF.Web.Geometry.Geometry;
  
  // THE FOLLOWING LINE RETURNS NULL
  ESRI.ArcGIS.Geometry.IGeometry featureInterface = 
      adfFeature as ESRI.ArcGIS.Geometry.IGeometry;
  
  ESRI.ArcGIS.Geometry.ITopologicalOperator topoOp = 
      adfFeature as ESRI.ArcGIS.Geometry.ITopologicalOperator;
  </code></pre>
  
  <p>How to use the IGeometry interface with an ADF Geometry object?</p>
  
  <p>I can't really find samples to intersect features between two layers, and it's a pity that Spatial Joins are just a arcgis desktop function, I surely could use them!</p>