GIS-判断点是否落在指点的多边形区域内

来源：互联网发布：网络工程施工规范编辑：程序博客网时间：2024/05/17 03:08
        /// <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;            }        }