ArcGIS Engine——坐标系相关

    public class SpatialReferenceHelpers
    {

        /// <summary>
        /// 创建地理坐标系
        /// </summary>
        /// <param name="FactoryCode"></param>
        /// <returns></returns>
        public ISpatialReference CreateGeographicSpatialReference(ESRI.ArcGIS.Geometry.esriSRGeoCSType FactoryCode)
        {
            return CreateGeographicSpatialReference((int)FactoryCode);
        }
        public ISpatialReference CreateGeographicSpatialReference(int FactoryCode)
        {
            ISpatialReferenceFactory2 oSpatialReferenceFactory;
            ISpatialReference oCS;
            try
            {
                Type t = Type.GetTypeFromProgID("esriGeometry.SpatialReferenceEnvironment");
                oSpatialReferenceFactory = (ISpatialReferenceFactory2)Activator.CreateInstance(t);
                oCS = oSpatialReferenceFactory.CreateSpatialReference(FactoryCode);
                return oCS;
            }
            catch
            {
                return null;
            }
        }



        /// <summary>
        ///  创建投影坐标系
        /// </summary>
        /// <param name="pcsType"></param>
        /// <returns></returns>
        public ISpatialReference CreateProjectSpatialReference(esriSRProjCS4Type pcsType)
        {
            return CreateProjectSpatialReference((int)pcsType);
        }
        public ISpatialReference CreateProjectSpatialReference(int FactoryCode)
        {
            ISpatialReferenceFactory2 oSpatialReferenceFactory;
            ISpatialReference oCS;
            try
            {
                Type t = Type.GetTypeFromProgID("esriGeometry.SpatialReferenceEnvironment");
                oSpatialReferenceFactory = (ISpatialReferenceFactory2)Activator.CreateInstance(t);
                oCS = oSpatialReferenceFactory.CreateProjectedCoordinateSystem(FactoryCode);
                return oCS;
            }
            catch
            {
                return null;
            }
        }



        /// <summary>
        /// 图形坐标系变换
        /// </summary>
        /// <param name="pGeometry"></param>
        /// <param name="pInputSR"></param>
        /// <param name="pOutputSR"></param>
        /// <returns></returns>
        public IGeometry TransformShapeCS(IGeometry pGeometry, ISpatialReference pInputSR, ISpatialReference pOutputSR)
        {
            IGeometry oGeometry;
            try
            {
                oGeometry = pGeometry;
                oGeometry.SpatialReference = pInputSR;
                oGeometry.Project(pOutputSR);
                return oGeometry;
            }
            catch
            {
                return pGeometry;
            }
        }
        /// <summary>  
        /// 修改要素集空间参考  
        /// </summary>  
        /// <param name="pFeatureDataset">要素集</param>  
        /// <param name="pSpatialReference">新空间参考</param>  
        public static void AlterSpatialReference(IFeatureDataset pFeatureDataset, ISpatialReference pSpatialReference)
        {
            IGeoDataset pGeoDataset = pFeatureDataset as IGeoDataset;
            IGeoDatasetSchemaEdit pGeoDatasetSchemaEdit = pGeoDataset as IGeoDatasetSchemaEdit;
            if (pGeoDatasetSchemaEdit.CanAlterSpatialReference == true)
                pGeoDatasetSchemaEdit.AlterSpatialReference(pSpatialReference);
        }



        /// <summary>  
        /// 获取要素集空间参考  
        /// </summary>  
        /// <param name="pGeoDataset">要素集</param>  
        /// <returns></returns>  
        public static ISpatialReference GetSpatialReference(IGeoDataset pGeoDataset)
        {
            return pGeoDataset.SpatialReference;
        }
        public static ISpatialReference GetSpatialReference(IFeatureDataset pFeatureDataset)
        {
            return GetSpatialReference(pFeatureDataset as IGeoDataset);
        }
        public static ISpatialReference GetSpatialReference(IFeatureLayer pFeatureLayer)
        {
            return GetSpatialReference(pFeatureLayer.FeatureClass);
        }
        public static ISpatialReference GetSpatialReference(IFeatureClass pFeatureClass)
        {
            return GetSpatialReference(pFeatureClass as IGeoDataset);
        }

    }