• 加入点对象过程:

 Dim objStyle As New soStyle
objStyle.PenColor = RGB(255, 0, 0)
objStyle.SymbolSize = 20
Dim objPoint As soGeoPoint
Select Case myPoints.Count
         Case 0
                     sm.TrackingLayer.ClearEvents
                    sm.TrackingLayer.AddEvent sm.TrackedGeometry, objStyle, "Point1"

                    Set objPoint = sm.TrackedGeometry
                    myPoints.Add2 objPoint.x, objPoint.y
                    sm.TrackingLayer.Refresh
          Case 1
                      Set objPoint = sm.TrackedGeometry
                     myPoints.Add2 objPoint.x, objPoint.y

'在trackinglayer上面显示第一点和第二点之间的连线
                    sm.TrackingLayer.RemoveEvent "Line"
                    Dim objPoints1 As New soPoints
                    Dim objLine1 As New soGeoLine
                    objPoints1.Add myPoints.Item(1)
                     objPoints1.Add myPoints.Item(2)
                     objLine1.AddPart objPoints1
                     objStyle.PenStyle = 2
                     objStyle.PenColor = RGB(196, 196, 196)
                    sm.TrackingLayer.AddEvent objLine1, objStyle, "Line1"

                     objStyle.PenColor = RGB(255, 0, 0)
                     sm.TrackingLayer.AddEvent sm.TrackedGeometry, objStyle, "Point2"

                     sm.TrackingLayer.Refresh
            Case 2
                     Set objPoint = sm.TrackedGeometry
                    myPoints.Add2 objPoint.x, objPoint.y

                    Dim objArc As New soGeoArc
                     objArc.MakeWith3P myPoints.Item(1), myPoints.Item(2), myPoints.Item(3)
                     Set objArc.Style = objStyle
                     Dim objRSet As soRecordset
                     Set objRSet = sm.Layers(1).Dataset.Query("SmID<0", True)
                     objRSet.AddNew objArc
                     objRSet.Update

                    sm.TrackingLayer.ClearEvents
                    myPoints.RemoveAll

                   sm.Refresh
End Select

• 三点画弧示意图