经纬度点与投影坐标系下坐标点的互相转换是AE编程中经常遇到的，下面以WGS84 和北京54为例介绍如何转换

源码如下：
 ''' <summary>
  ''' 将经纬度点转换为某投影下的坐标点
  ''' </summary>
  ''' <param name="pPoint">经纬度点</param>
  ''' <returns>某投影下的坐标点</returns>
  ''' <remarks>其中pPoint的X是经度，Y是纬度，单位都是度，千万不要搞错，否则转换出来的值是不对的或转换不出值</remarks>
  Private Function GetProjectPoint(ByVal pPoint As IPoint) As IPoint
    Dim pSRF As ISpatialReferenceFactory = New SpatialReferenceEnvironment
    pPoint.SpatialReference = pSRF.CreateGeographicCoordinateSystem(esriSRGeoCSType.esriSRGeoCS_WGS1984)
    pPoint.Project(pSRF.CreateProjectedCoordinateSystem(esriSRProjCSType.esriSRProjCS_Beijing1954GK_23N))
    Return pPoint
  End Function
  ''' <summary>
  ''' 将点转换为经纬度点
  ''' </summary>
  ''' <param name="x">点X坐标</param>
  ''' <param name="y">点Y坐标</param>
  ''' <returns>经纬度点</returns>
  ''' <remarks></remarks>
  Private Function GetGeoPoint(ByVal x As Double, ByVal y As Double) As IPoint
    Dim pProPoint As IPoint = New Point
    pProPoint.PutCoords(x, y)
    Dim pSRF As ISpatialReferenceFactory = New SpatialReferenceEnvironment
    pProPoint.SpatialReference = pSRF.CreateProjectedCoordinateSystem(esriSRProjCSType.esriSRProjCS_Beijing1954GK_23N) 
    pProPoint.Project(pSRF.CreateGeographicCoordinateSystem(esriSRGeoCSType.esriSRGeoCS_WGS1984))
    Return pProPoint
  End Function