link: http://www.cnblogs.com/yhlx125/p/3635623.html
Shape comparison language
首先说说我遇到的一个问题：
IRelationalOperator.Overlaps方法使用的时候无法查询得到所有的相交对象。看下说明，相交部分包含在每一个对象中而不等有任何一个对象。
Two geometries overlap if the region of their intersection is of the same dimension as the geometries involved and is not equivalent to either of the geometries. Overlaps is a Clementini operator.
还有就是在使用ITopologicalOperator.Intersect方法返回的IGeometry不是null，而是需要通过其属性IsEmpty来判断！
空间关系用查询几何体和被请求的几何体的边界，内部，外部之间的相交关系来定义。
Each character in the string represents a relationship between the query geometry and the geometry being tested, and can have a value of T (true), F (false), or * (not tested).
The following table shows the relationships represented by each character:
| Requested geometry | |||
Interior | Boundary | Exterior | ||
Query geometry | Interior | 1 | 2 | 3 |
Boundary | 4 | 5 | 6 | |
Exterior | 7 | 8 | 9 | |
扩展九交模型
作者：yhexie
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