多源数据综合分析时，最好先将坐标系进行统一（投影坐标系为佳）
ArcObjects 10 .NET SDK Help Understanding coordinate management in ArcGIS
To achieve precise and predictable results using the geometry library, it is essential that the spatial reference of geometries in a workflow is well defined. When performing a spatial operation using two or more geometries, for example, an intersection, the coordinate systems of the two geometries must be equal. If the coordinate systems of the geometries are different or undefined, the operation can produce unexpected results.
为了使用几何图形库获得精确且可预测的结果，至关重要的是，必须明确定义工作流程中几何图形的空间参考。当使用两个或多个几何图形（例如相交线）执行空间操作时，两个几何图形的坐标系必须相等。如果几何的坐标系不同或不确定，则该操作可能会产生意外的结果。
