获取面或线的节点坐标问题

不明白为什么会产生多余的两个点,特来探讨一下,程序如下,红色为获取选中的图块方法.

Dim pPolygon As IPolygon
Dim pGeom As IGeometry
Dim pFeatureLayer As IFeatureLayer
Dim pFeatureCursor As IFeatureCursor
Dim pFesyureClass As IFeatureClass
Dim pWorkspaceEdit As IWorkspaceEdit
Dim pFeature As iFeature
Dim pActiveView As IActiveView
Dim pPointColn As IPointCollection

If m_pCurrentLayer Is Nothing Then Exit Sub
Set pFeatureLayer = m_pCurrentLayer
Set pFeatureClass = pFeatureLayer.FeatureClass
Set pFeatureCursor = GetSelectedFeatures
If pFeatureCursor Is Nothing Then Exit Sub
Set pWorkspaceEdit = GetWorkspaceEdit
pWorkspaceEdit.StartEditOperation
Set pFeature = pFeatureCursor.NextFeature
Set pPointColn = pFeature.Shape
MsgBox pPointColn.PointCount
Dim i As Integer
For i = 0 To pPointColn.PointCount - 1
 MsgBox CStr(pPointColn.Point(i).x) + "," + CStr(pPointColn.Point(i).y)
Next

pWorkspaceEdit.StopEditOperation
Set pActiveView = m_pMap
pActiveView.refresh

图1:

从pPointColn.PointCount 得到五个节点

1.-140.965,8.682

2.-128.801,4.355

3.-124.637,11.131

4.-124.637,11.131

5.-140.965,8.682

明明只是个三角形,确得到五个点,看图,我们很显然知道4,5是错的.

图2:同样我们画了一个五边形,也得到了七个点,也只有前五个是正确的.

1.-145.17,21.70

2.-133.38,13.39

3.-130.03,17.01

4.-129.89,22.51

5.-136.73,26.80

6.-136.86,26.80

7.-145.17,21.7

我也是这样想的,可能是取了两次

为什么会取两次？

起点和终点取了两次?

现在没办法测试,周一上班再看了,希望看到你的好消息