having trouble calculating distance in centimeters through windows phone
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I developed an app to read distance between two locations on windows phone 7 . But while testing the app, whenever i move some centimeters, it starts to give value in 13000's. 

Public Sub watcher1_PositionChanged(sender As Object, e As GeoPositionChangedEventArgs(Of GeoCoordinate))
        Dim dCoord As GeoCoordinate
        Dim currentDistance As Double
        Dim convertedDistance As Double
        dCoord = New GeoCoordinate(e.Position.Location.Latitude, e.Position.Location.Longitude)

        If mlastCoordinate.Latitude <> 0.0 Then

            'distanceText.Text = e.Position.Location.Latitude.ToString()
            currentDistance = mlastCoordinate.GetDistanceTo(dCoord)
            mDistance = startCoordinate.GetDistanceTo(dCoord)
            ' mDistance += currentDistance
            'mDistance = Math.Round(mDistance, 2)
            'Dim distance As String
            'distance = String.Format("%.2", mDistance)
            If selectedSystemState.Equals("centi") Then
                convertedDistance = mDistance * 100
            ElseIf selectedSystemState.Equals("meter") Then
                convertedDistance = mDistance
            ElseIf selectedSystemState.Equals("inches") Then
                convertedDistance = mDistance * 39.37
            ElseIf selectedSystemState.Equals("feet") Then
                convertedDistance = mDistance * 3.28
            End If
            
            convertedDistance = Math.Round(convertedDistance, 2)
    

