Hello,About a year ago I played around with MapTopology to see what one could do with it. The code below is in VBA and shows you how you could identify dangling nodes. The limitation of this method is that it works only when you are in edit mode.Duncan
Public Sub SelectDanglingPolylines()
' Description: Takes a polyline dataset and select all dangling polylines.
'
' Requirements: You need to be in edit mode and have added the layer to a MAP TOPOLOGY,
' also polyline layer must be first in TOC.
'
' Limitations: Large datasets take a long time to build the cache and may even fail.
'
' Author: Duncan Hornby
' Created: 11/12/2011
'
' Get map and then first layer, must be of polyline type
Dim pMXDocument As IMxDocument
Set pMXDocument = ThisDocument
Dim pMap As IMap
Set pMap = pMXDocument.FocusMap
Dim pLayer As ILayer
Set pLayer = pMap.Layer(0)
Dim pFeatureLayer As IFeatureLayer
Set pFeatureLayer = pLayer
Dim pFeatureClass As IFeatureClass
Set pFeatureClass = pFeatureLayer.FeatureClass
If pFeatureClass.ShapeType <> esriGeometryPolyline Then
MsgBox "This code works only with polylines!", vbExclamation, "Wrong data type at layer 0"
Exit Sub
End If
' Get editor and topology extension
Dim pEditor As IEditor
Dim pID As New UID
Dim pTopologyExtension As ITopologyExtension
Dim pTEID As New UID
pID = "esriEditor.editor"
Set pEditor = Application.FindExtensionByCLSID(pID)
pTEID = "esriEditorExt.TopologyExtension"
Set pTopologyExtension = Application.FindExtensionByCLSID(pTEID)
If pTopologyExtension.CurrentTopology Is Nothing Then Exit Sub
' Get a MAP topology not a geodatabase topology
Dim pMapTopology As IMapTopology
If TypeOf pTopologyExtension.CurrentTopology Is IMapTopology Then
Set pMapTopology = pTopologyExtension.MapTopology
Else
' Not a Map Topology
Exit Sub
End If
' This is the colection that FID are added to
Dim aColl As New Collection
' Build cache
Application.StatusBar.Message(0) = "Building MAP TOPOLOGY cache, this can take a long time on large datasets..."
DoEvents
Dim pGeoDataset As IGeoDataset
Set pGeoDataset = pFeatureClass
Dim pEnvelope As IEnvelope
Set pEnvelope = pGeoDataset.Extent
pMapTopology.Cache.Build pEnvelope, False
' Identify dangling nodes and add polyline FID to collection
Application.StatusBar.Message(0) = "Identifying dangling nodes..."
DoEvents
Dim pEnumTopologyParent As IEnumTopologyParent
Dim pTopologyNode As ITopologyNode
Dim pEnumTopologyNode As IEnumTopologyNode
Set pEnumTopologyNode = pMapTopology.Cache.Nodes
pEnumTopologyNode.Reset
Set pTopologyNode = pEnumTopologyNode.Next
While Not pTopologyNode Is Nothing
If pTopologyNode.Degree = 1 Then
' As this has 1 degree it has only 1 parent polyline
Set pEnumTopologyParent = pTopologyNode.Parents
pEnumTopologyParent.Reset
aColl.Add (pEnumTopologyParent.Next.m_FID) 'Adds polyline FID to collection
End If
Set pTopologyNode = pEnumTopologyNode.Next
Wend
' Use collection to select polylines
Application.StatusBar.Message(0) = "Selecting polylines..."
DoEvents
Dim pFeatureSelection As IFeatureSelection
Set pFeatureSelection = pFeatureLayer
Dim X As Variant
For Each X In aColl
pFeatureSelection.SelectionSet.Add CLng(X)
Next
pMXDocument.ActiveView.PartialRefresh esriViewGeoSelection, Nothing, pEnvelope
Application.StatusBar.Message(0) = ""
DoEvents
End Sub
