/// <summary>
/// Traverse the topology graph, <see cref="ITopologyGraph"/>, to visit topology elements <see cref="ITopologyElement"/>
/// </summary>
/// <param name="featureDataset">Feature dataset object</param>
/// <param name="topologyName">The topology name</param>
/// <param name="featureClassName">The feature class name</param>
/// <param name="originFeatureObjectId">Feature ObjectId from the feature class, <paramref name="featureClassName"/></param>
/// <returns>A JSON object <see cref="JsonObject"/> containing parcels' id and address</returns>
/// <remarks>
/// This method builds the topology graph around origin parcel feature and traverse the topology graph to fetch its adjoining parcels and their addresses
/// </remarks>
public JsonObject TraverseTopologyGraph(IFeatureDataset featureDataset, string topologyName, string featureClassName, int originFeatureObjectId)
{
// Fetch feature class by name
IFeatureClass parcelFeatureClass = GetFeatureClass(featureDataset, featureClassName);
// Fetch topology by name from feature dataset
ITopology topology = GetTopologyFromFeatureDataset(featureDataset, topologyName);
// Get the origin parcel feature identified by ObjectID
IFeature parcelFeature = GetFeature(parcelFeatureClass, originFeatureObjectId);
ITopologyGraph topologyGraph = topology.Cache;
// Build the topology graph around the origin parcel feature
topologyGraph.Build(parcelFeature.Shape.Envelope, false);
IEnumTopologyEdge enumTopologyEdge = topologyGraph.GetParentEdges(parcelFeatureClass, originFeatureObjectId);
enumTopologyEdge.Reset();
List <dynamic> taxParcelIds = new List <dynamic>();
IEnvelope topologyParentsEnvelope = new EnvelopeClass();
Dictionary <int, IPoint> parcelsToCentroidMap = new Dictionary <int, IPoint>();
for (int topoEdgeCount = 0; topoEdgeCount < enumTopologyEdge.Count; topoEdgeCount++)
{
ITopologyEdge topologyEdge = enumTopologyEdge.Next();
// Parents of the topology edge
IEnumTopologyParent parents = topologyEdge.Parents;
parents.Reset();
for (int parentsCount = 0; parentsCount < parents.Count; parentsCount++)
{
esriTopologyParent parent = parents.Next();
int parentFID = parent.m_FID;
IFeatureClass parentFC = parent.m_pFC;
IFeature parentParcelFeature = parentFC.GetFeature(parentFID);
// Get the index of 'ParcelType' field from the parcel feature class
int parcelTypeIndex = parentParcelFeature.Fields.FindField("PARCELTYPE");
// Get parcel type value
int parcelTypeValue = Convert.ToInt32(parentParcelFeature.Value[parcelTypeIndex]);
// Avoid duplicates and skip parcels with 'RowOverlap' subtype
if (parentFC == parcelFeatureClass && !taxParcelIds.Contains(parentFID) && parentFID != originFeatureObjectId && (parcelTypeValue < 8 && parcelTypeValue > 0))
{
taxParcelIds.Add(parentFID);
// Envelope of a parcel
IEnvelope parcelEnvelope = parentParcelFeature.Extent.Envelope;
// Centroid of a parcel
IArea parcelArea = parcelEnvelope as IArea;
IPoint parcelCentroid = parcelArea.Centroid;
// Add parcel id and centroid to the mapping dictionary
parcelsToCentroidMap.Add(parentFID, parcelCentroid);
// Union of the adjoining parcels' envelope
topologyParentsEnvelope.Union(parcelEnvelope);
}
}
}
// Update topology graph to include adjoining parcels
topologyGraph.Build(topologyParentsEnvelope, false);
JsonObject jsonObject = new JsonObject();
// Get adjoining parcels and their addresses
List <string> parcelWithAddressList = GetParcelsWithAddress(topologyGraph, parcelsToCentroidMap);
// Format JSON array
jsonObject.AddArray($"Adjoining parcels of {originFeatureObjectId}", parcelWithAddressList?.ToArray());
return(jsonObject);
}
