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
- Start ArcMap.
- In the Project Explorer window, expand Project.mxt and select ArcMap Objects > ThisDocument. Right-click and select View Code.-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.
- Copy/Paste the following code into the code module.
- Option Explicit
- Public Sub SelectPolyAsSharesSegementWith()
- Dim pMxDoc As IMxDocument
- Set pMxDoc = ThisDocument
- Dim pMap As IMap
- Set pMap = pMxDoc.FocusMap
- ' Union all of the search features into one geometry and strip off
- ' it's boundary for use in the search. Since we are only interested
- ' in shared segments, not areas, the boundary is all that is needed.
- ' Get search layer
- Dim pPolygonLyr As IFeatureLayer
- Set pPolygonLyr = pMap.Layer(1)
- Dim pLFeatClass As IFeatureClass
- Set pLFeatClass = pPolygonLyr.FeatureClass
- ' Loop through the polygons, simplify them and then
- ' add them to a Geometry Bag.
- Dim pFeatureCursor As IFeatureCursor
- Set pFeatureCursor = pLFeatClass.Search(Nothing, True)
- Dim pFeature As IFeature
- Set pFeature = pFeatureCursor.NextFeature
- Dim pGeometryCollection As IGeometryCollection
- Set pGeometryCollection = New GeometryBag
- Dim pTopologicalOperator2 As ITopologicalOperator2
- Do While Not pFeature Is Nothing
- Set pTopologicalOperator2 = pFeature.ShapeCopy
- pTopologicalOperator2.IsKnownSimple = False
- pTopologicalOperator2.Simplify
- pGeometryCollection.AddGeometry pTopologicalOperator2
- Set pFeature = pFeatureCursor.NextFeature
- Loop
- ' Union all the polygons
- Dim pTopologicalOperator1 As ITopologicalOperator2
- Set pTopologicalOperator1 = New Polygon
- pTopologicalOperator1.ConstructUnion pGeometryCollection
- ' Construct the boundary of the unioned polygons
- Dim pTopologicalOperator3 As ITopologicalOperator2
- Set pTopologicalOperator3 = New Polyline
- Set pTopologicalOperator3 = pTopologicalOperator1.Boundary
- ' Use the boundary to find the candidate features
- ' Get the target FeatureClass
- Dim pFeatureLayer As IFeatureLayer
- Set pFeatureLayer = pMap.Layer(0)
- Dim pFeatureClass As IFeatureClass
- Set pFeatureClass = pFeatureLayer.FeatureClass
- ' Set up a scratch workspace to use for the selection
- Dim pScratchWorkspace As IWorkspace
- Dim pScratchWorkspaceFactory As IScratchWorkspaceFactory
- Set pScratchWorkspaceFactory = New ScratchWorkspaceFactory
- Set pScratchWorkspace = pScratchWorkspaceFactory.DefaultScratchWorkspace
- ' Setup the spatial filter
- Dim pSpatialFilter As ISpatialFilter
- Set pSpatialFilter = New SpatialFilter
- With pSpatialFilter
- Set .Geometry = pTopologicalOperator3
- .GeometryField = "SHAPE"
- .SpatialRel = esriSpatialRelIntersects
- End With
- ' Perform the search and create a selection set
- Dim pTempSelection As ISelectionSet
- Set pTempSelection = pFeatureClass.Select(pSpatialFilter, esriSelectionTypeIDSet, esriSelectionOptionNormal, pScratchWorkspace)
- ' Loop through the features and check to see if they share a segment
- ' with the search geometry. If they don't, remove them from the selection
- ' set.
- ' Create a feature cursor to allow us the examine the candidate features
- Dim pTempFeatCur As IFeatureCursor
- pTempSelection.Search Nothing, True, pTempFeatCur
- Dim iOIDList(1) As Long
- Dim iOIDListCount As Long
- iOIDListCount = 1
- Dim pGeometry As IPolyline
- Dim pTempFeat As IFeature
- ' Fetch the first feature
- Set pTempFeat = pTempFeatCur.NextFeature
- Dim pTempPolyline As IPolyline
- ' Check for the one dimentional intersection of the geometries.
- ' If there is no intersection the returned geometry will be empty. If
- ' it is, remove it from the selection set.
- Dim pTopologicalOperator4 As ITopologicalOperator2
- Set pTopologicalOperator4 = New Polygon
- Do
- iOIDList(0) = pTempFeat.OID
- Set pTopologicalOperator4 = pTempFeat.ShapeCopy
- pTopologicalOperator4.IsKnownSimple = False
- pTopologicalOperator4.Simplify
- Set pTempPolyline = pTopologicalOperator4.Boundary
- Set pGeometry = pTopologicalOperator3.Intersect(pTempPolyline, esriGeometry1Dimension)
- If pGeometry.IsEmpty Then
- pTempSelection.RemoveList iOIDListCount, iOIDList(0)
- End If
- Set pTempFeat = pTempFeatCur.NextFeature
- Loop Until pTempFeat Is Nothing
- ' Set the feature selection
- Dim pFeatureSelection As IFeatureSelection
- Set pFeatureSelection = pFeatureLayer
- Set pFeatureSelection.SelectionSet = pTempSelection
- ' Display the selected features.
- Dim pdoc As IMxDocument
- Set pdoc = ThisDocument
- pdoc.ActiveView.Refresh
End Sub
- Close the Visual Basic Editor.
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