两点经纬度之间距离计算

辅助类

GaoDeCoord.cs

GaoDeCoord.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Text;

namespace RB.Common
{
    #region 高德地图求范围自有数据
    /// <summary>  
    /// 经纬度坐标  
    /// </summary>   
    public class Degree
    {
        public Degree(double x, double y)
        {
            X = x;
            Y = y;
        }
        private double x;
        public double X
        {
            get { return x; }
            set { x = value; }
        }

        private double y;
        public double Y
        {
            get { return y; }
            set { y = value; }
        }
    }


    public class CoordDispose
    {
        //WGS84坐标系
        private const double EARTH_RADIUS = 6378137.0;//地球半径(米) 

        /// <summary> 
        /// 弧度转换为角度数公式 
        /// </summary> 
        /// <param name="d"></param> 
        /// <returns></returns> 
        private static double degrees(double d)
        {
            return d * (180 / Math.PI);
        }

        /// <summary> 
        /// 以一个经纬度为中心计算出四个顶点 
        /// </summary> 
        /// <param name="distance">半径(米)</param> 
        /// <returns></returns> 
        public static Degree[] GetDegreeCoordinates(Degree Degree1, double distance)
        {
            double dlng = 2 * Math.Asin(Math.Sin(distance / (2 * EARTH_RADIUS)) / Math.Cos(Degree1.X));
            dlng = degrees(dlng);//一定转换成角度数 

            /***
             *       |←0.435→|
             *   ——  —————————————————
             *   ↑   |       |       |
             *   0.5 |       |       |
             *   ↓   |       |       |
             *   ——  |———————|———————|
             *       |       |       |
             *       |       |       |
             *       |       |       |
             *       —————————————————
             *       0.5*2/0.435*2=1.149
             *       如果需要求左右范围内所有数据，所以就需要*1.149
             * ***/
            distance = distance * 1.149;

            double dlat = distance / EARTH_RADIUS;
            dlat = degrees(dlat);//一定转换成角度数 

            return new Degree[] { new Degree(Math.Round(Degree1.X + dlat,6), Math.Round(Degree1.Y - dlng,6)),//left-top
                                 new Degree(Math.Round(Degree1.X - dlat,6), Math.Round(Degree1.Y - dlng,6)),//left-bottom
                                 new Degree(Math.Round(Degree1.X + dlat,6), Math.Round(Degree1.Y + dlng,6)),//right-top
                                 new Degree(Math.Round(Degree1.X - dlat,6), Math.Round(Degree1.Y + dlng,6)) //right-bottom
           };
        }


        /// <summary>
        /// 获取两个经纬度之间的距离
        /// </summary>
        /// <param name="LonA">经度A</param>
        /// <param name="LatA">纬度A</param>
        /// <param name="LonB">经度B</param>
        /// <param name="LatB">经度B</param>
        /// <returns>距离（米）</returns>
        public static double getDistance(double LonA, double LatA, double LonB, double LatB)
        {
            // 东西经，南北纬处理，只在国内可以不处理(假设都是北半球，南半球只有澳洲具有应用意义)
            double MLonA = LonA;
            double MLatA = LatA;
            double MLonB = LonB;
            double MLatB = LatB;
            // 地球半径（千米）
            //double R = 6371.004;
            // 地球半径（米）
            //double R = 6378137.0;

            double C = Math.Sin(rad(LatA)) * Math.Sin(rad(LatB)) + Math.Cos(rad(LatA)) * Math.Cos(rad(LatB)) * Math.Cos(rad(MLonA - MLonB));
            return (EARTH_RADIUS * Math.Acos(C));
        }

        /// <summary>
        /// 角度数转换为弧度公式
        /// </summary>
        /// <param name="d"></param>
        /// <returns></returns>
        private static double rad(double d)
        {
            return d * Math.PI / 180.0;
        }

        /// <summary>
        /// 冒泡排序
        /// </summary>
        /// <param name="m"></param>
        /// <returns></returns>
        public static double[] sort(double[] m)
        {
            //执行多少次
            for (double i = 0; i < m.Length; i++)
            {
                //每执行1次，将最大的排在最后
                //m.Length-1，因为 m[j + 1] <= m[5]
                for (int j = 0; j < m.Length - 1; j++)
                {
                    double a = m[j];
                    double b = m[j + 1];
                    if (a > b)
                    {
                        m[j + 1] = a;
                        m[j] = b;
                    }
                }
            } return m;
        }
    }

    #endregion
}

 

 

调用方法

Recommend

Recommend

        #region 04 推荐好友 + Recommend
        /// <summary>
        /// 推荐好友
        /// </summary>
        /// <param name="userid">关注者ID</param>
        /// <param name="longitude">经度</param>
        /// <param name="latitude">纬度</param>
        /// <returns></returns>
        public JsonResponse Recommend(int userid, double longitude, double latitude)
        {
            //设置查询距离
            int distance = int.Parse(ConfigurationManager.AppSettings["Distance"].ToString());

            //获取不了经纬度，默认为（0，0）
            if (longitude == 0 && latitude == 0)
            {
                var z = new SelectSqlSection<DTemporaryRecord>().Join<DUserDetail>((a, b) => a.User_id == b.User_id).Take(10);
                IList<UserDetail> list = DDataBase.DataBase.ToIList<UserDetail>(z);
                //返回个人信息
                return Response.ReturnFun(list);
            }

            //1.设定范围求圆的4个角度
            Degree[] dd = CoordDispose.GetDegreeCoordinates(new Degree(longitude, latitude), distance);

            //2.使用冒泡排序求最大值和最小值 X,Y
            double[] arrX = { dd[0].X, dd[1].X, dd[2].X, dd[3].X };
            double[] arrY = { dd[0].Y, dd[1].Y, dd[2].Y, dd[3].Y };
            //从小到大
            double[] vvX = CoordDispose.sort(arrX);
            double[] vvY = CoordDispose.sort(arrY);

            //3.经度在X最小值和最大值范围内，纬度同上
            var xyz = new SelectSqlSection<DTemporaryRecord>().Join<DUserDetail>((a, b) => a.User_id == b.User_id).
                Where(a => a.PositionX > vvX[0] && a.PositionX < vvX[3] && a.PositionY > vvY[0] && a.PositionY < vvY[3]).
                Take(10);

            var xylist = DDataBase.DataBase.ToDataSet(xyz).Tables[0];

            //4.在圆的4个角度范围内 更精确查询每个点的距离
            for (int i = 0; i < xylist.Rows.Count; i++)
            {
                double DIST = CoordDispose.getDistance(longitude, latitude, double.Parse(xylist.Rows[i].ItemArray[2].ToString()), double.Parse(xylist.Rows[i].ItemArray[3].ToString()));
                //如果得到的距离大于设定的距离，则去掉
                if (DIST > distance)
                {
                    xylist.Rows.Remove(xylist.Rows[i]);
                    i--;    //游标也需要跟着-1
                }
            }

            #region 数据库交互
            //判断 （临时表） 关注者ID
            var xxx = new SelectSqlSection<DTemporaryRecord>().Where(a => a.User_id == userid);
            IList<TemporaryRecord> realTimelist = DDataBase.DataBase.ToIList<TemporaryRecord>(xxx);

            TemporaryRecord ret = new TemporaryRecord();
            ret.User_id = userid;
            ret.PositionX = longitude;
            ret.PositionY = latitude;
            if (realTimelist == null || realTimelist.Count == 0)
            {
                //添加并返回id
                int id = DDataBase.DataBase.InsertScalar(ret);
            }
            else
            {
                //修改
                ret.Id = realTimelist[0].Id;
                DDataBase.DataBase.Update(ret);
            }
            #endregion

            //返回查询的结果
            return Response.ReturnFun(xylist);
        }
        #endregion