ESRI ArcGIS应用与开发切割问题||做专业的GIS技术交流论坛

gsl1982 路人甲注册日期2004-05-08 发帖数135 QQ 铜币543枚威望0点贡献值0点银元0个加关注写私信	阅读：1675回复：1 切割问题楼主^# 更多只看楼主倒序阅读发布于：2004-10-21 09:52 <P>请问，在屏幕上画个矩形或多边形，如何得到矩形或多边形内的要素，要素和矩形相交的要切割。但不切割原图层要素，只是临时得到切割后的要素！</P> <P>如何实现阿，用什么库，什么接口？</P>
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发布于：2004-10-21 16:09

在ao的帮助里有个Cut polygons sample，你可以看看Description:

<TEXT>This sample duplicates the 'Cut Polygon Features' task but uses a polygon edit sketch instead of a polyline edit sketch. This task makes it easier to create doughnut polygons for example. The illustration below shows an edit sketch being drawn over a single selected feature. Finishing the sketch creates a new feature by cutting it out from the selected feature. 'This task sets the edit sketch geometry to polygon type and uses this
<CODE>'geometry as a cookie cutter on selected features</CODE>

<CODE>Option Explicit

Implements</CODE> IEditTask

<CODE>Private</CODE> m_pEditor <CODE>As</CODE> IEditor
<CODE>Private</CODE> m_pEdSketch <CODE>As</CODE> IEditSketch
<CODE>Private</CODE> m_pMxDoc <CODE>As</CODE> IMxDocument
<CODE>Private WithEvents</CODE> EditorEvents <CODE>As</CODE> Editor

<CODE>Private Sub</CODE> IEditTask_Activate(<CODE>ByVal</CODE> Editor <CODE>As</CODE> esriEditor.IEditor, <CODE>ByVal</CODE> oldTask <CODE>As</CODE> esriEditor.IEditTask)
 <CODE>Set</CODE> m_pEditor = Editor
 <CODE>Set</CODE> EditorEvents = Editor
 <CODE>Set</CODE> m_pEdSketch = Editor
 <CODE>Set</CODE> m_pMxDoc = Editor.Parent.Document
 <CODE>'Call Selection changed to see if the sketch tools should be enabled</CODE>
 EditorEvents_OnSelectionChanged
<CODE>End Sub

Private Sub</CODE> IEditTask_Deactivate()
 <CODE>'When the task is deactivated, stop listening for events</CODE>
 <CODE>Set</CODE> EditorEvents = <CODE>Nothing
End Sub

Private Property Get</CODE> IEditTask_Name() <CODE>As String</CODE>
 IEditTask_Name = "Cut Polygons by Area" <CODE>'Give our task a name</CODE>
<CODE>End Property

Private Sub</CODE> IEditTask_OnDeleteSketch()

<CODE>End Sub

Private Sub</CODE> IEditTask_OnFinishSketch()
 <CODE>On Error GoTo</CODE> handler:

 <CODE>Dim</CODE> pRefreshArea <CODE>As</CODE> IInvalidArea <CODE>'Used to specify the area of the display to refresh</CODE>
 <CODE>Dim</CODE> pOrigFeature <CODE>As</CODE> IFeature <CODE>'The selected feature</CODE>
 <CODE>Dim</CODE> pNewFeature <CODE>As</CODE> IFeature <CODE>'New feature created during operation</CODE>
 <CODE>Dim</CODE> pEnumFeat <CODE>As</CODE> IEnumFeature
 <CODE>Dim</CODE> pCutGeom <CODE>As</CODE> IGeometry <CODE>'The geometry that performs the cut - edit sketch</CODE>
 <CODE>Dim</CODE> pRemainder <CODE>As</CODE> IGeometry <CODE>'Difference between edit sketch and orig feature (modified orig feature)</CODE>
 <CODE>Dim</CODE> pSubDivision <CODE>As</CODE> IGeometry <CODE>'Intersection between edit sketch and orig feaure (new feature)</CODE>
 <CODE>Dim</CODE> pFeatureClass <CODE>As</CODE> IFeatureClass <CODE>'The feature class in which to place new features</CODE>
 <CODE>Dim</CODE> pTopoOperator <CODE>As</CODE> ITopologicalOperator
 <CODE>Dim</CODE> pFields <CODE>As</CODE> IFields
 <CODE>Dim</CODE> pField <CODE>As</CODE> IField
 <CODE>Dim</CODE> FieldCount <CODE>As Integer</CODE>

 <CODE>'Start an edit operation so we can have undo/redo</CODE>
 m_pEditor.StartOperation

 <CODE>'Get ready to invalidate the features</CODE>
 <CODE>Set</CODE> pRefreshArea = <CODE>New</CODE> InvalidArea

 <CODE>Set</CODE> pCutGeom = m_pEdSketch.Geometry <CODE>'Get the cutting geometry from the edit sketch</CODE>
 <CODE>Set</CODE> pTopoOperator = pCutGeom
 pTopoOperator.Simplify <CODE>' make sure the edit sketch geometry is simple</CODE>

 <CODE>Set</CODE> pEnumFeat = m_pEditor.EditSelection <CODE>'Get the selected set of editable features</CODE>
 pEnumFeat.Reset
 <CODE>Set</CODE> pOrigFeature = pEnumFeat.Next <CODE>'Get the next feature in the enumeration (the first one in this case)</CODE>
 <CODE>If</CODE> pOrigFeature <CODE>Is Nothing Then GoTo</CODE> handler <CODE>'abort the operation if nothing is selected</CODE>

 <CODE>'Start a loop for each feature in the selection</CODE>
 <CODE>Do While Not</CODE> pOrigFeature <CODE>Is Nothing</CODE>

 <CODE>'Only process polygon features</CODE>
 <CODE>If</CODE> pOrigFeature.Shape.GeometryType = esriGeometryPolygon <CODE>Then</CODE>

 pRefreshArea.Add pOrigFeature <CODE>'Add the feature to the invalidate object</CODE>

 <CODE>Set</CODE> pTopoOperator = pOrigFeature.Shape
 <CODE>Set</CODE> pSubDivision = pTopoOperator.Intersect(pCutGeom, esriGeometry2Dimension)

 <CODE>If Not</CODE> pSubDivision.IsEmpty <CODE>Then
 Set</CODE> pFeatureClass = pOrigFeature.Class
 <CODE>Set</CODE> pNewFeature = pFeatureClass.CreateFeature <CODE>'Create a new Feature in the same feature class</CODE>
 <CODE>Set</CODE> pNewFeature.Shape = pSubDivision <CODE>'Put the subdivided portion into this feature</CODE>

 <CODE>'Set the original featuer's shape to the results returned from the difference</CODE>
 <CODE>Set</CODE> pRemainder = pTopoOperator.Difference(pCutGeom)
 <CODE>Set</CODE> pOrigFeature.Shape = pRemainder

 <CODE>'copy the attributes of the orig feature the new feature</CODE>
 <CODE>Set</CODE> pFields = pOrigFeature.Fields
 <CODE>For</CODE> FieldCount = 0 <CODE>To</CODE> pFields.FieldCount - 1 <CODE>'skip OID and geometry</CODE>
 <CODE>Set</CODE> pField = pOrigFeature.Fields.Field(FieldCount)
 <CODE>If Not</CODE> pField.Type = esriFieldTypeGeometry <CODE>And Not</CODE> pField.Type = esriFieldTypeOID _
 <CODE>And</CODE> pField.Editable <CODE>Then</CODE>
 pNewFeature.Value(FieldCount) = pOrigFeature.Value(FieldCount)
 <CODE>End If
 Next</CODE> FieldCount

 pOrigFeature.Store <CODE>'Now store the original feature with the remainder geometry</CODE>
 pNewFeature.Store <CODE>'Store the subdivided feature</CODE>
 <CODE>End If

 End If</CODE> <CODE>'End check for polygons</CODE>

 <CODE>Set</CODE> pOrigFeature = pEnumFeat.Next <CODE>'Get the next feature in the selection</CODE>
 <CODE>Loop</CODE>

 m_pMxDoc.FocusMap.ClearSelection <CODE>'Clear the map's selection</CODE>

 <CODE>'Refresh the display</CODE>
 <CODE>Set</CODE> pRefreshArea.Display = m_pEditor.Display
 pRefreshArea.Invalidate esriAllScreenCaches <CODE>'Update the display</CODE>

 m_pEditor.StopOperation ("Cut Polygon Features") <CODE>'Complete the edit operation</CODE>

 <CODE>Exit Sub</CODE>

handler:
 MsgBox "Unable to perform the cut task."
 m_pEditor.AbortOperation <CODE>'In the event of an error, abort the operation</CODE>
<CODE>End Sub

Private Sub</CODE> EditorEvents_OnSelectionChanged()
 <CODE>'Only enabled the sketch tools if there is something selected</CODE>
 <CODE>If</CODE> m_pEditor.SelectionCount = 0 <CODE>Then</CODE>
 m_pEdSketch.GeometryType = esriGeometryNull
 <CODE>Else</CODE>
 m_pEdSketch.GeometryType = esriGeometryPolygon <CODE>'Set the edit sketch geometry type</CODE>
 <CODE>End If
End Sub</CODE>

GIS麦田守望者，期待与您交流。

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