ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Data.Topology Namespace / TopologyGraph Class / FindClosestElement<T> Method
The type of topological element.
The location used to find the nearest topological element to it.
The search radius units for queryPoint.
Example Version

FindClosestElement<T> Method
Finds a topological element in the topology graph closest to the location specified by queryPoint that is also within searchRadius units. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public T FindClosestElement<T>( 
   MapPoint queryPoint,
   double searchRadius
)
where T: TopologyElement

Parameters

queryPoint
The location used to find the nearest topological element to it.
searchRadius
The search radius units for queryPoint.

Type Parameters

T
The type of topological element.

Return Value

The topological element of type T nearest to queryPoint if it exists; otherwise, null.
Exceptions
ExceptionDescription
A geodatabase-related exception has occurred.
Example
FindClosestElement
public void FindClosestElement()
{
  using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri(@"C:\TestData\GrandTeton.gdb"))))
  using (Topology topology = geodatabase.OpenDataset<Topology>("Backcountry_Topology"))
  {
    // Build a topology graph using the extent of the topology dataset.

    topology.BuildGraph(topology.GetExtent(), (topologyGraph) =>
    {
      MapPoint queryPointViaCampsites12 = null;

      using (Feature campsites12 = GetFeature(geodatabase, "Campsites", 12))
      {
        queryPointViaCampsites12 = campsites12.GetShape() as MapPoint;
      }

      double searchRadius = 1.0;

      TopologyElement topologyElementViaCampsites12 = 
          topologyGraph.FindClosestElement<TopologyElement>(
                    queryPointViaCampsites12, searchRadius);

      System.Diagnostics.Debug.Assert(
        topologyElementViaCampsites12 != null, "There should be a topology element corresponding to 'queryPointViaCampsites12' within the 'searchRadius' units.");

      IReadOnlyList<FeatureInfo> parentFeatures = topologyElementViaCampsites12.GetParentFeatures();

      Console.WriteLine("The parent features that spawn 'topologyElementViaCampsites12' are:");
      foreach (FeatureInfo parentFeature in parentFeatures)
      {
        Console.WriteLine($"\t{parentFeature.FeatureClassName}; OID: {parentFeature.ObjectID}");
      }

      TopologyNode topologyNodeViaCampsites12 = topologyGraph.FindClosestElement<TopologyNode>(queryPointViaCampsites12, searchRadius);

      if (topologyNodeViaCampsites12 != null)
      {
        // There exists a TopologyNode nearest to the query point within searchRadius units.
      }

      TopologyEdge topologyEdgeViaCampsites12 = topologyGraph.FindClosestElement<TopologyEdge>(queryPointViaCampsites12, searchRadius);

      if (topologyEdgeViaCampsites12 != null)
      {
        // There exists a TopologyEdge nearest to the query point within searchRadius units.
      }
    });
  }
}
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also