求助(根据经纬度打点)

求助根据经纬度打点  例如:
 'x,y分别表示经度和纬度
  Dim pt As MapObjects2.Point
  Dim x, y As Double
  x=30.5
  y=20.5
  Map1.FromMapPoint pt, x, y
  Map1.TrackingLayer.AddEvent pt, 0
但结果却在"Map1.FromMapPoint pt, x, y"处出现"Type mismatch"错误,请问该怎么写

'建立一组点,进行跟踪
Dim pt As MapObjects2.Point
Set m_ptsTrack = New MapObjects2.Points
Set pt = New MapObjects2.Point
pt.Set -79.3062, 39.9254
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -79.0407, 39.5037
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -78.7127, 39.2694
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -78.291, 39.2694
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -77.8069, 39.4256
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -77.4008, 39.6599
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -77.026, 39.7536
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -76.6511, 39.6911
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -76.2763, 39.41
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -75.9483, 39.0196
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -75.839, 38.6916
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -75.511, 38.2855
m_ptsTrack.Add pt
Set pt = New MapObjects2.Point
pt.Set -75.3704, 37.9419
m_ptsTrack.Add pt

OK 了   <img src="images/post/smile/dvbbs/em04.gif" />