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[ASP.net教程]计算地理位置之间的距离


 .net 根据坐标,计算指定范围内的最大最小经纬度、根据两点间经纬度坐标(double值),计算两点间距离(注意:这里的单位是米)

 #region 根据坐标,计算指定范围内的最大最小经纬度、根据两点间经纬度坐标(double值),计算两点间距离,单位为米    private static double PI = Math.PI; //3.14159265; //π    private static double EARTH_RADIUS = 6378137;  //地球半径    private static double RAD = Math.PI / 180.0;  //  π/180    #region 根据坐标,计算指定范围内的最大最小经纬度    /// <summary>    /// 根据坐标,计算指定范围内的最大最小经纬度    /// </summary>    /// <param name="lng">经度</param>    /// <param name="lat">纬度</param>    /// <param name="raidus">范围(米)</param>    /// <returns>返回最大、最小经纬度minLng, minLat, maxLng, maxLat</returns>    public double[] getAround(double lng, double lat, int raidus)    {      //The circumference of the earth is 24,901 miles.      //24,901/360 = 69.17 miles / degree       Double latitude = lat;      Double longitude = lng;      Double degree = (24901 * 1609) / 360.0;  //地球的周长是24901英里      double raidusMile = raidus;      //先计算纬度      Double dpmLat = 1 / degree;      Double radiusLat = dpmLat * raidusMile;      Double minLat = latitude - radiusLat;      Double maxLat = latitude + radiusLat;      //计算经度      Double mpdLng = degree * Math.Cos(latitude * (PI / 180)); //纬度的余弦      Double dpmLng = 1 / mpdLng;      Double radiusLng = dpmLng * raidusMile;      Double minLng = longitude - radiusLng;      Double maxLng = longitude + radiusLng;      //System.out.println("["+minLat+","+minLng+","+maxLat+","+maxLng+"]");                //最小经度,最小纬度,最大经度,最大纬度      return new double[] { minLng, minLat, maxLng, maxLat };    }    #endregion    #region 根据两点间经纬度坐标(double值),计算两点间距离,单位为米    /// <summary>    /// 根据两点间经纬度坐标(double值),计算两点间距离,单位为米    /// </summary>    /// <param name="lng1">经度1</param>    /// <param name="lat1">纬度1</param>    /// <param name="lng2">经度2</param>    /// <param name="lat2">纬度2</param>    /// <returns>返回距离(米)</returns>    public double getDistance(double lng1, double lat1, double lng2, double lat2)    {      double radLat1 = lat1 * RAD; // // RAD=π/180      double radLat2 = lat2 * RAD;      double a = radLat1 - radLat2;      double b = (lng1 - lng2) * RAD;      double s = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) +       Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));      s = s * EARTH_RADIUS;      s = Math.Round(s * 10000) / 10000;      return s;    }    #endregion    #endregion


 

sql:计算地球上两个坐标点(经度,纬度)之间距离sql函数(注意:这里的单位是千米)

go  --计算地球上两个坐标点(经度,纬度)之间距离sql函数  CREATE FUNCTION [dbo].[fnGetDistance](@LatBegin REAL, @LngBegin REAL, @LatEnd REAL, @LngEnd REAL) RETURNS FLOAT  AS BEGIN  --距离(千米)  DECLARE @Distance REAL  DECLARE @EARTH_RADIUS REAL  SET @EARTH_RADIUS = 6378.137   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 END 

sql转自:http://www.aspbc.com/tech/showtech.asp?id=1136
百度地图获取两点间的距离在线测试:http://developer.baidu.com/map/jsdemo.htm#a6_1