ArcGIS Engine坐标点单位转换（由米转化为经纬度）

　　//获取图层IFeatureClass

var lqpkFC = lqpkLayer.FeatureClass;

//获取图层坐标系统
var pSpatialRef = (lqpkFC as IGeoDataset).SpatialReference;
var pProCoordSys = pSpatialRef as IProjectedCoordinateSystem;
var pGeographCoordinateSys =pProCoordSys.GeographicCoordinateSystem;

//坐标系转换,将投影坐标转换为对应的地理坐标
IGeometry pGeo = (IGeometry) centerPoint;
pGeo.SpatialReference = pProCoordSys;
pGeo.Project(pGeographCoordinateSys);