HowTo Perform the spatial selection 'Share a line segment with' using ArcObjects

HowTo  Perform the spatial selection 'Share a line segment with' using ArcObjects

Article ID:	26528
Software:	ArcGIS - ArcEditor 8.1, 8.1.2, 8.2, 8.3 ArcGIS - ArcInfo 8.1, 8.1.2, 8.2, 8.3 ArcGIS - ArcView 8.1, 8.1.2, 8.2, 8.3
Platforms:	Windows NT 4.0, 2000, XP

Summary

Instructions provided illustrate how to duplicate the functionality of ArcMap's spatial selection 'share a line segment with' through ArcObjects code.

 

Procedure

1. Start ArcMap.
2. Open the Visual Basic Editor. -show me-
3. In the Project Explorer window, expand Project.mxt and select ArcMap Objects > ThisDocument. Right-click and select .-show me- 

    Code in the Project's ThisDocument code module will only run in the current map document. If you want to store the code in all map documents open the Normal.mxt ThisDocument code module.

    

4. Copy/Paste the following code into the code module. 
5. Option Explicit
6.  
7. Public Sub SelectPolyAsSharesSegementWith()
8.  
9. Dim pMxDoc As IMxDocument
10. Set pMxDoc = ThisDocument
11. Dim pMap As IMap
12. Set pMap = pMxDoc.FocusMap
13.  
14. ' Union all of the search features into one geometry and strip off
15. ' it's boundary for use in the search. Since we are only interested
16. ' in shared segments, not areas, the boundary is all that is needed.
17.  
18. ' Get search layer
19. Dim pPolygonLyr As IFeatureLayer
20. Set pPolygonLyr = pMap.Layer(1)
21. Dim pLFeatClass As IFeatureClass
22. Set pLFeatClass = pPolygonLyr.FeatureClass
23.  
24. ' Loop through the polygons, simplify them and then
25. ' add them to a Geometry Bag.
26. Dim pFeatureCursor As IFeatureCursor
27. Set pFeatureCursor = pLFeatClass.Search(Nothing, True)
28. Dim pFeature As IFeature
29. Set pFeature = pFeatureCursor.NextFeature
30. Dim pGeometryCollection As IGeometryCollection
31. Set pGeometryCollection = New GeometryBag
32. Dim pTopologicalOperator2 As ITopologicalOperator2
33.  
34. Do While Not pFeature Is Nothing
35. Set pTopologicalOperator2 = pFeature.ShapeCopy
36. pTopologicalOperator2.IsKnownSimple = False
37. pTopologicalOperator2.Simplify
38. pGeometryCollection.AddGeometry pTopologicalOperator2
39. Set pFeature = pFeatureCursor.NextFeature
40. Loop
41.  
42. ' Union all the polygons
43. Dim pTopologicalOperator1 As ITopologicalOperator2
44. Set pTopologicalOperator1 = New Polygon
45. pTopologicalOperator1.ConstructUnion pGeometryCollection
46.  
47. ' Construct the boundary of the unioned polygons
48. Dim pTopologicalOperator3 As ITopologicalOperator2
49. Set pTopologicalOperator3 = New Polyline
50. Set pTopologicalOperator3 = pTopologicalOperator1.Boundary
51.  
52. ' Use the boundary to find the candidate features
53.  
54. ' Get the target FeatureClass
55. Dim pFeatureLayer As IFeatureLayer
56. Set pFeatureLayer = pMap.Layer(0)
57. Dim pFeatureClass As IFeatureClass
58. Set pFeatureClass = pFeatureLayer.FeatureClass
59.  
60. ' Set up a scratch workspace to use for the selection
61. Dim pScratchWorkspace As IWorkspace
62. Dim pScratchWorkspaceFactory As IScratchWorkspaceFactory
63. Set pScratchWorkspaceFactory = New ScratchWorkspaceFactory
64. Set pScratchWorkspace = pScratchWorkspaceFactory.DefaultScratchWorkspace
65.  
66. ' Setup the spatial filter
67. Dim pSpatialFilter As ISpatialFilter
68. Set pSpatialFilter = New SpatialFilter
69. With pSpatialFilter
70. Set .Geometry = pTopologicalOperator3
71. .GeometryField = "SHAPE"
72. .SpatialRel = esriSpatialRelIntersects
73. End With
74.  
75. ' Perform the search and create a selection set
76. Dim pTempSelection As ISelectionSet
77. Set pTempSelection = pFeatureClass.Select(pSpatialFilter, esriSelectionTypeIDSet, esriSelectionOptionNormal, pScratchWorkspace)
78.  
79. ' Loop through the features and check to see if they share a segment
80. ' with the search geometry. If they don't, remove them from the selection
81. ' set.
82.  
83. ' Create a feature cursor to allow us the examine the candidate features
84. Dim pTempFeatCur As IFeatureCursor
85. pTempSelection.Search Nothing, True, pTempFeatCur
86.  
87. Dim iOIDList(1) As Long
88. Dim iOIDListCount As Long
89. iOIDListCount = 1
90. Dim pGeometry As IPolyline
91. Dim pTempFeat As IFeature
92.  
93. ' Fetch the first feature
94. Set pTempFeat = pTempFeatCur.NextFeature
95. Dim pTempPolyline As IPolyline
96.  
97. ' Check for the one dimentional intersection of the geometries.
98. ' If there is no intersection the returned geometry will be empty. If
99. ' it is, remove it from the selection set.
100.  
101. Dim pTopologicalOperator4 As ITopologicalOperator2
102. Set pTopologicalOperator4 = New Polygon
103.  
104. Do
105. iOIDList(0) = pTempFeat.OID
106.  
107. Set pTopologicalOperator4 = pTempFeat.ShapeCopy
108.  
109. pTopologicalOperator4.IsKnownSimple = False
110. pTopologicalOperator4.Simplify
111.  
112. Set pTempPolyline = pTopologicalOperator4.Boundary
113.  
114. Set pGeometry = pTopologicalOperator3.Intersect(pTempPolyline, esriGeometry1Dimension)
115. If pGeometry.IsEmpty Then
116. pTempSelection.RemoveList iOIDListCount, iOIDList(0)
117. End If
118.  
119. Set pTempFeat = pTempFeatCur.NextFeature
120. Loop Until pTempFeat Is Nothing
121.  
122. ' Set the feature selection
123. Dim pFeatureSelection As IFeatureSelection
124. Set pFeatureSelection = pFeatureLayer
125. Set pFeatureSelection.SelectionSet = pTempSelection
126.  
127. ' Display the selected features.
128. Dim pdoc As IMxDocument
129. Set pdoc = ThisDocument
130. pdoc.ActiveView.Refresh
131.  

     End Sub

      

132. Close the Visual Basic Editor.
133. Run the code. -show me-

 

Created: 4/1/2004
Last Modified: 7/1/2008

Article Rating:  (1)

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Comments

By Anonymous - 07/20/2005 7:47 AM

Hello, The sample code to select polygons that share a segment with the selected polygon did not work for me. Although I tested it in 9.1, no library is explicitly defined so I don't think this is the problem. http://support.esri.com/index.cfm?fa=knowledgebase.techarticles.articleShow&d=26528 Sincerely, Valentina