Engine中如何修改要素类或者栅格数据的空间参考？

【解决办法】：
​使用IGeoDatasetSchemaEdit.AlterSpatialReference方法修改空间参考（这里相当于ArcMap中Define Projection工具的作用，只是修改了空间参考，但是数据并没有进行投影，要与Project相区别），可参考下面代码： 

IGeoDataset geodataset = featureClass as IGeoDataset; //栅格的话就把IRasterDataset转为IGeoDataset

            ISchemaLock schemaLock = (ISchemaLock)geodataset;

            schemaLock.ChangeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);

            IGeoDatasetSchemaEdit geoDatasetSchemaEdit = geodataset as IGeoDatasetSchemaEdit;

            if (geoDatasetSchemaEdit.CanAlterSpatialReference)

            {

                ISpatialReferenceFactory3 spatialReferenceFactory = new SpatialReferenceEnvironmentClass();

                ISpatialReference spatialReference = spatialReferenceFactory.CreateGeographicCoordinateSystem((int)esriSRGeoCSType.esriSRGeoCS_Beijing1954) as ISpatialReference;

                geoDatasetSchemaEdit.AlterSpatialReference(spatialReference);

            }

            schemaLock.ChangeSchemaLock(esriSchemaLock.esriSharedSchemaLock);