1.创建空间参考

        /// <summary>
        /// 根据prj文件创建空间参考
        /// </summary>
        /// <param name="strProFile">空间参照文件</param>
        /// <returns></returns>
        public static ISpatialReference CreateSpatialReference(string strProFile)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironmentClass();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateESRISpatialReferenceFromPRJFile(strProFile);
            return pSpatialReference;           
        }

        /// <summary>
        /// 创建地理坐标系
        /// </summary>
        /// <param name="gcType">esriSRProjCS4Type</param>
        /// <returns></returns>
        public static ISpatialReference CreateGeographicCoordinate(esriSRProjCS4Type gcsType)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironmentClass();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateGeographicCoordinateSystem((int)gcsType);
            return pSpatialReference;
        }

        /// <summary>
        /// 创建投影坐标系
        /// </summary>
        /// <param name="pcType">esriSRProjCS4Type</param>
        /// <returns></returns>
        public static ISpatialReference CreateProjectedCoordinate(esriSRProjCS4Type pcsType)
        {
            ISpatialReferenceFactory2 pSpatialReferenceFactory = new SpatialReferenceEnvironmentClass();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateProjectedCoordinateSystem((int)pcsType);
            return pSpatialReference;
        }

        /// <summary>
        /// 获取空投影
        /// </summary>
        /// <returns></returns>
        public static ISpatialReference CreateUnKnownSpatialReference()
        {
            ISpatialReference pSpatialReference = new UnknownCoordinateSystemClass();
            pSpatialReference.SetDomain(0, 99999999, 0, 99999999);//设置空间范围
            return pSpatialReference;
        }

2.获取空间参考

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

        /// <summary>
        /// 获取要素层空间参考
        /// </summary>
        /// <param name="pFeatureLayer">要素层</param>
        /// <returns></returns>
        public static ISpatialReference GetSpatialReferenc(IFeatureLayer pFeatureLayer)
        {IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;
            IGeoDataset pGeoDataset = pFeatureClass as IGeoDataset;
            ISpatialReference pSpatialReference = pGeoDataset.SpatialReference;
            return pSpatialReference;           
        }

        /// <summary>
        /// 获取要素类空间参考
        /// </summary>
        /// <param name="pFeatureClass">要素类</param>
        /// <returns></returns>
        public static ISpatialReference GetSpatialReference(IFeatureClass pFeatureClass)
        {
            IGeoDataset pGeoDataset = pFeatureClass as IGeoDataset;
            ISpatialReference pSpatialReference = pGeoDataset.SpatialReference;
            return pSpatialReference;           
        }

3.修改空间参考

        /// <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>
        /// 修改要素类空间参考
        /// </summary>
        /// <param name="pFeatureClass">要素类</param>
        /// <param name="pSpatialReference">新空间参考</param>
        public static void AlterSpatialReference(IFeatureClass pFeatureClass, ISpatialReference pSpatialReference)
        {
            IGeoDataset pGeoDataset = pFeatureClass as IGeoDataset;
            IGeoDatasetSchemaEdit pGeoDatasetSchemaEdit = pGeoDataset as IGeoDatasetSchemaEdit;
            if (pGeoDatasetSchemaEdit.CanAlterSpatialReference == true)
                pGeoDatasetSchemaEdit.AlterSpatialReference(pSpatialReference);
        }