public static IPoint XY2JYD(ISpatialReference aSR, IPoint pXY) { IPoint point = new ESRI.ArcGIS.Geometry.Point(); point = (pXY as IClone).Clone() as IPoint; if (aSR == null) { return(point); } if (aSR.Name != "Unknown") { point.SpatialReference = aSR; point.SnapToSpatialReference(); if (aSR is IProjectedCoordinateSystem) { IGeographicCoordinateSystem system = (aSR as IProjectedCoordinateSystem).GeographicCoordinateSystem; point.Project(system); } return(point); } return(null); }