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
