转载自：http://blog.csdn.net/anlidengshiwei/article/details/40377437
先来看看ITopologicalOperator的成员：截图来自帮助文档：
简要介绍下各个成员的汉语翻译：
1、Boundary，边界，获取一个Geometry的边界；
用法：
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ITopologicalOperator pTopologBoundary = pGeo as ITopologicalOperator;
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IGeometry pGeometry = pTopologBoundary.Boundary;
（1）多边形Polygon的边界获取的是Polyline
（2）Polyline获得的是IPiontColletion点集；（3）点没有边界
2、Buffer，缓冲区，可以为点、线、面做缓冲区，参数为缓冲区范围的大小，大于0向外做缓冲区，小于0向内做缓冲区；
用法：
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ITopologicalOperator pTopologBoundary = pGeo as ITopologicalOperator;
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Geometry pGeometry = pTopologBoundary.Buffer(2);
3、Clip，叠加裁剪，从源图层中裁剪掉分割图层后的图形；参数类型为IEnvelope类型
用法：
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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pTopologBoundary.Clip(pClipGeometry.Envelope as IEnvelope);
4、Cut，分割，将一个Geometry分割为两部分。
用法：
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IGeometry pSourceGeometry = null, pClipGeometry = null;
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IGeometry pLeftGeo,pRightGo;
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IPolyline pPolyline=null;
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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pTopologBoundary.Cut(pPolyline, out pLeftGeo, out pRightGo);
5、Difference，区别，保留下源图层与操作图层中不同的部分。
用法：
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IGeometry pSourceGeometry = null, pDifGeometry = null;
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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IGeometry pResultGeo= pTopologBoundary.Difference(pDifGeometry);
6、Intersect，相交，求两个图层相交，返回IGeometry对象
用法：
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ITopologicalOperator pTopological = (pSubFeature.Shape) as ITopologicalOperator;
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IGeometry pGeoIntersect=pTopological.Intersect(pFeature.Shape, esriGeometryDimension.esriGeometry2Dimension);
7、IsSimple，是否拓扑闭合
用法：
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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bool bIsSimple = pTopologBoundary.IsSimple;
8、Simplify，使一个Geometry拓扑闭合；
用法：
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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pTopologBoundary.Simplify();
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<pre name=“code” class=“csharp”>IGeometry pSourceGeometry = null, pUnionGeometry = null;
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ITopologicalOperator pTopologBoundary = pSourceGeometry as ITopologicalOperator;
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IGeometry pUnionGeo=pTopologBoundary.Union(pUnionGeometry);
转载自：https://blog.csdn.net/knqiufan/article/details/78019404
