IHit3D接口

我用IHit3D接口获得了一组点，但是一个屏幕坐标传入，最后它会返回很多个点，请问我知道三维地图里我鼠标位置的地图X,Y,Z坐标，请问哪个点才是它的三维坐标对应点。

<P>看看这个例子</P>
<H1>LocateMultiple Example</H1><CODE><PRE>'<BR>' Call this method to examine on the 3D Hits in the active viewer.<BR>' For example, from the ArcScene Tools | Customize | Commands | UIControls<BR>' dialog, create a new UIToolControl to allow for mouse clicks, and in the<BR>' UIToolControl's MouseDown event, pass the x and y screen coordinates<BR>' to this method:<BR>'<BR>'  Private Sub UIToolControl_MouseDown(ByVal button As Long, ByVal shift As Long, ByVal x As Long, ByVal y As Long)<BR>'<BR>'    ReportScreenPick x, y<BR>'<BR>'  End Sub<BR>'<BR>Public Sub ReportScreenPick(xScreen As Long, yScreen As Long)</PRE><PRE>  ' local variables:<BR>  Dim x As Long, y As Long<BR>  x = xScreen<BR>  y = yScreen<BR>  <BR>  ' reference ths scenegraph object in the scene:<BR>  Dim pSXDoc As ISxDocument<BR>  Set pSXDoc = ThisDocument<BR>  Dim pSG As ISceneGraph<BR>  Set pSG = pSXDoc.Scene.SceneGraph<BR>  <BR>  ' call the scenegraph's LocateMultiple method for the designated<BR>  ' location in the active viewer:<BR>  Dim pHits As IHit3DSet<BR>  pSG.LocateMultiple pSG.ActiveViewer, x, y, esriScenePickAll, True, pHits<BR>  <BR>  If pHits Is Nothing Then<BR>    MsgBox "No hits were returned."<BR>    Exit Sub<BR>  End If<BR>  <BR>  Dim i As Integer<BR>  Dim pHit As IHit3D<BR>  <BR>  MsgBox pHits.Hits.Count ; " hit(s) were returned - review the output in the VBA Immediate Window."<BR>  Debug.Print pHits.Hits.Count ; " Hit(s) at screen location " ; x ; ", " ; y ; ":"<BR>  <BR>  ' for each hit returned, report on its properties:<BR>  For i = 0 To pHits.Hits.Count - 1<BR>    Set pHit = pHits.Hits.Element(i)<BR>    Debug.Print "Hit " ; i + 1<BR>    With pHit<BR>      If TypeOf .Owner Is ILayer Then<BR>        Dim pLayer As ILayer<BR>        Set pLayer = .Owner<BR>        Debug.Print "  Owner(Layer): " ; pLayer.name<BR>      End If<BR>      <BR>      If Not .Object Is Nothing Then<BR>        If TypeOf .Object Is IFeature Then<BR>          Dim pFeature As IFeature<BR>          Set pFeature = .Object<BR>          Debug.Print "  Feature ID: " ; pFeature.OID<BR>        End If<BR>      End If<BR>      <BR>      Debug.Print "  Distance from the Observer to the Hit point: " ; .DistanceToObserver<BR>      Debug.Print "  Distance between the Hit point and the picking ray: " ; .DistanceToRay<BR>      Debug.Print "  Exact Hit: " ; .ExactHit<BR>      Debug.Print "  Geographic location: " ; .Point.x ; ", " ; .Point.y ; ", " ; .Point.Z<BR>      <BR>      Dim nDepthMin As Double, nDepthMax As Double<BR>      .GetDepthRange nDepthMin, nDepthMax<BR>      Debug.Print "  OpenGL Depth Range: " ; nDepthMin ; " - " ; nDepthMax<BR>      <BR>    End With<BR>    <BR>  Next</PRE><PRE>End Sub<BR></PRE></CODE>