GIS-判断点是否落在指点的多边形区域内_arcgis 判断点是否在面内-优快云博客

本文详细介绍了如何通过编程方法判断一个指定的坐标点是否位于给定多边形区域之内，包括算法流程、关键步骤以及代码实现。

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        /// <summary>
        /// 判断坐标点是否落在指定的多边形区域内
        /// </summary>
        /// <param name="point">指定的坐标点</param>
        /// <param name="list">多变形区域的节点集合</param>
        /// <returns>True 落在范围内 False 不在范围内</returns>
        public bool IsWithIn(ESRI.ArcGIS.Client.Geometry.MapPoint point, List<ESRI.ArcGIS.Client.Geometry.MapPoint> list)
        {
            double x = point.X;
            double y = point.Y;

            int isum, icount, index;
            double dLon1 = 0, dLon2 = 0, dLat1 = 0, dLat2 = 0, dLon;

            if (list.Count < 3)
            {
                return false;
            }

            isum = 0;
            icount = list.Count;

            try
            {
                for (index = 0; index < icount - 1; index++)
                {
                    if (index == icount - 1)
                    {
                        dLon1 = list[index].X;
                        dLat1 = list[index].Y;
                        dLon2 = list[0].X;
                        dLat2 = list[0].Y;
                    }
                    else
                    {
                        dLon1 = list[index].X;
                        dLat1 = list[index].Y;
                        dLon2 = list[index + 1].X;
                        dLat2 = list[index + 1].Y;
                    }

                    if (((y >= dLat1) && (y < dLat2)) || ((y >= dLat2) && (y < dLat1)))
                    {
                        if (Math.Abs(dLat1 - dLat2) > 0)
                        {
                            dLon = dLon1 - ((dLon1 - dLon2) * (dLat1 - y)) / (dLat1 - dLat2);
                            if (dLon < x)
                                isum++;
                        }
                    }
                }
            }
            catch { }

            if ((isum % 2) != 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }