Arcgis Engine（ae）接口详解（5）：IGeometry几何高级操做

IPoint point = new PointClass();
            point.PutCoords(100, 200);

            //ITopologicalOperator接口用于几何对象的几何操做
            ITopologicalOperator topo = point as ITopologicalOperator;
            //作一个几何对象的缓冲区（结果也是个几何对象），参数1是缓冲半径
            //点线面的缓冲区都是面，因此能够直接as到IPolygon
            IPolygon polygon = topo.Buffer(100) as IPolygon;

            ITopologicalOperator2 topo2 = point as ITopologicalOperator2;
            //错误几何对象的修复，若是当几何对象有几何错误，例如面有自相交，能够用此修复
            topo2.IsKnownSimple_2 = false;
            topo2.Simplify();

            topo = polygon as ITopologicalOperator;
            //获取面的边，面的边是线
            IPolyline polyline = topo.Boundary as IPolyline;

            IPolygon polygon2 = new PolygonClass();

            topo = polygon as ITopologicalOperator;
            //求两个几何对象的重叠部分
            //两个几何对象的重叠部分，能够有不少种几何类型组合，例如面与面重叠是面，线与线重叠是线或者点，点与点重叠是点，点与面重叠是点，线与面重叠是线等等
            //参数2是返回结果是多少维的意思，根据经验若是返回结果是点就是0维（esriGeometry0Dimension），线就是1维，面就是2维            
            //官方文档还有详细说明，使用者要结合文档和实际使用状况相互对照来学习
            IGeometry geometry3 = topo.Intersect(polygon2, esriGeometryDimension.esriGeometry2Dimension);

            //两个几何对象的几何操做还有：
            //Union 求两个几何对象合并后的，也就是求并集
            //Clip 裁剪
            //Cut 用线把面一份为二
            //Difference 擦除

            //IRelationalOperator用于判断两个几何对象的空间关系
            //IRelationalOperator的每种空间关系在官方文档有具体截图
            IRelationalOperator relaOper = polygon as IRelationalOperator;
            //求两个几何对象是否有重叠部分，注意：Overlaps判断的两个几何对象的几何类型必须相同
            bool result = relaOper.Overlaps(polygon2);

            //其余空间关系判断有：
            //Contains-彻底包含
            //Crosses-穿过？
            //Disjoint-彻底不相交
            //Equals-彻底重叠（就是两个几何对象彻底同样，经常使用！！！！！）
            //Touches-边沿重叠？
            //Within-彻底包含2

            IPoint point2 = new PointClass();
            point.PutCoords(200, 300);

            //计算两点距离
            double distance = GeometryHelper.TwoPointDistance(point, point2);

调用的封装函数

/// <summary>
        /// 计算两点距离
        /// </summary>
        /// <param name="point1"></param>
        /// <param name="point2"></param>
        /// <returns></returns>
        public static double TwoPointDistance(IPoint point1, IPoint point2)
        {
            if (point1 == null || point2 == null) return 0;

            return TwoPointDistance(point1.X, point1.Y, point2.X, point2.Y);
        }

        /// <summary>
        /// 计算两点距离
        /// </summary>
        /// <param name="x1"></param>
        /// <param name="y1"></param>
        /// <param name="x2"></param>
        /// <param name="y2"></param>
        /// <returns></returns>
        public static double TwoPointDistance(double x1, double y1, double x2, double y2)
        {
            return Math.Sqrt(Math.Pow(x1 - x2, 2) + Math.Pow(y1 - y2, 2));
        }