Arcgis Engine（ae）接口詳解（5）：IGeometry幾何高級操做

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

            //ITopologicalOperator接口用於幾何對象的幾何操做
            ITopologicalOperator topo = point as ITopologicalOperator;
            //作一個幾何對象的緩衝區（結果也是個幾何對象），參數1是緩衝半徑
            //點線面的緩衝區都是面，因此能夠直接as到IPolygon
            IPolygon polygon = topo.Buffer(100) as IPolygon;

            ITopologicalOperator2 topo2 = point as ITopologicalOperator2;
            //錯誤幾何對象的修復，若是當幾何對象有幾何錯誤，例如面有自相交，能夠用此修復
            topo2.IsKnownSimple_2 = false;
            topo2.Simplify();

            topo = polygon as ITopologicalOperator;
            //獲取面的邊，面的邊是線
            IPolyline polyline = topo.Boundary as IPolyline;

            IPolygon polygon2 = new PolygonClass();

            topo = polygon as ITopologicalOperator;
            //求兩個幾何對象的重疊部分
            //兩個幾何對象的重疊部分，能夠有不少種幾何類型組合，例如面與面重疊是面，線與線重疊是線或者點，點與點重疊是點，點與面重疊是點，線與面重疊是線等等
            //參數2是返回結果是多少維的意思，根據經驗若是返回結果是點就是0維（esriGeometry0Dimension），線就是1維，面就是2維            
            //官方文檔還有詳細說明，使用者要結合文檔和實際使用狀況相互對照來學習
            IGeometry geometry3 = topo.Intersect(polygon2, esriGeometryDimension.esriGeometry2Dimension);

            //兩個幾何對象的幾何操做還有：
            //Union 求兩個幾何對象合併後的，也就是求並集
            //Clip 裁剪
            //Cut 用線把面一份爲二
            //Difference 擦除

            //IRelationalOperator用於判斷兩個幾何對象的空間關係
            //IRelationalOperator的每種空間關係在官方文檔有具體截圖
            IRelationalOperator relaOper = polygon as IRelationalOperator;
            //求兩個幾何對象是否有重疊部分，注意：Overlaps判斷的兩個幾何對象的幾何類型必須相同
            bool result = relaOper.Overlaps(polygon2);

            //其餘空間關係判斷有：
            //Contains-徹底包含
            //Crosses-穿過？
            //Disjoint-徹底不相交
            //Equals-徹底重疊（就是兩個幾何對象徹底同樣，經常使用！！！！！）
            //Touches-邊沿重疊？
            //Within-徹底包含2

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

            //計算兩點距離
            double distance = GeometryHelper.TwoPointDistance(point, point2);

調用的封裝函數

/// <summary>
        /// 計算兩點距離
        /// </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>
        /// 計算兩點距離
        /// </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));
        }