微信lbs---返回两个经纬度坐标点的距离

微信开发：lbs附近的商家，在数据库里记录商家的坐标，lbs设置里管理搜索半径，查询的时候，查询 客户当前坐标的半径内的所有商家列表。
个人喜欢不一样，我选择了执行sql ，毕竟效果高点。微信开发必须得将就效率问题。不然等半天出不来，急死人，半天出不来结果，客户直接走人。
不多说，直接上代码

\\返回两个经纬度坐标点的距离（单位：米）

 

\\C#  方法

 

///<summary>返回两个经纬度坐标点的距离（单位：米） by Alex.Y</summary>

        ///<param name="Longtiude">来源坐标经度Y</param>

        ///<param name="Latitude">来源坐标经度X</param>

        ///<param name="Longtiude2">目标坐标经度Y</param>

        ///<param name="Latitude2">目标坐标经度X</param>

        ///<returns>返回距离（米）</returns>

        public double getMapDistance(double Longtiude, double Latitude, double Longtiude2, double Latitude2)

        {

 

            var lat1 = Latitude;

            var lon1 = Longtiude;

            var lat2 = Latitude2;

            var lon2 = Longtiude2;

            var earthRadius = 6371; //appxoximate radius in miles  6378.137

 

            var factor = Math.PI / 180.0;

            var dLat = (lat2 - lat1) * factor;

            var dLon = (lon2 - lon1) * factor;

            var a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) + Math.Cos(lat1 * factor)

              * Math.Cos(lat2 * factor) * Math.Sin(dLon / 2) * Math.Sin(dLon / 2);

            var c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));

 

            double d = earthRadius * c * 1000;

 

            return d;

 

        }

 

 

 

--返回两个经纬度坐标点的距离（单位：千米）

 

-- =============================================

-- Author:      alex.Y

-- Create date: getdate()

-- Description: 返回两个经纬度坐标点的距离（单位：千米）

--        ///<param name="@LngBegin">来源坐标经度Y</param>

--        ///<param name="@LatBegin">来源坐标经度X</param>

--        ///<param name="@LngEnd">目标坐标经度Y</param>

 --       ///<param name="@LatEnd">目标坐标经度X</param>

-- =============================================

 

CREATE FUNCTION [dbo].[ufn_GetMapDistance]

(@LngBegin  REAL, @LatBegin REAL, @LngEnd REAL, @LatEnd REAL)

       RETURNS FLOAT

       AS

BEGIN

       --距离(千米)  

       DECLARE @Distance      REAL

       DECLARE @EARTH_RADIUS  REAL

       --SET @EARTH_RADIUS =6378.137

       SET @EARTH_RADIUS =6371 

        

       DECLARE @RadLatBegin  REAL,

               @RadLatEnd    REAL,

               @RadLatDiff   REAL,

               @RadLngDiff   REAL

        

       SET @RadLatBegin = @LatBegin *PI()/ 180.0

       SET @RadLatEnd = @LatEnd *PI()/ 180.0

       SET @RadLatDiff = @RadLatBegin - @RadLatEnd

       SET @RadLngDiff = @LngBegin *PI()/ 180.0 - @LngEnd *PI()/ 180.0

        

       SET @Distance = 2 *ASIN(

               SQRT(

                   POWER(SIN(@RadLatDiff / 2), 2)+COS(@RadLatBegin)*COS(@RadLatEnd)

                   *POWER(SIN(@RadLngDiff / 2), 2)

               )

           )

        

       SET @Distance = @Distance * @EARTH_RADIUS

       --SET @Distance = Round(@Distance * 10000) / 10000

        

       RETURN @Distance

        

        -- SELECT [dbo].[ufn_GetMapDistance](116.3130497932434100,39.9804086267150800,116.3731849193573000,39.9110159284269700)

 

END