Calculate the distance between geographic locations

. NET calculates the maximum minimum latitude and longitude within a specified range based on coordinates, calculates the distance between two points according to the latitude and longitude coordinates of two points (note: The units here are meters)

#region calculates the maximum minimum latitude and longitude within a specified range according to coordinates, calculates the distance between two points, in meters private static, according to the latitude and longitude coordinates of two points (double value)Double PI =Math.PI;//3.14159265;//πprivate StaticDoubleEarth_radius= 6378137;//Earth radius private staticDoubleRad=Math.PI / 180.0;//Pi/ the#region calculates the maximum minimum latitude and longitude within a specified range based on coordinates/// <Summary>        ///calculates the maximum minimum latitude and longitude within a specified range, based on coordinates/// </Summary>        /// <param name="LNG">Longitude</Param>        /// <param name="Lat">Latitude</Param>        /// <param name="Raidus">Range (m)</Param>        /// <returns>Returns maximum, minimum latitude and longitude minlng, Minlat, MAXLNG, Maxlat</returns>         Public Double[]Getaround (DoubleLngDoubleLatintRaidus) {            //The circumference ofThe Earth is  -,901miles. // -,901/ the = 69.17Miles/degreeDoubleLatitude=lat; DoubleLongitude=LNG; DoubleDegree=(24901 * 1609)/ 360.0;//the perimeter of the earth is 24901 miles.DoubleRaidusmile=Raidus; //Calculate latitude FirstDoubleDpmlat= 1 /degree; DoubleRadiuslat=Dpmlat*Raidusmile; DoubleMinlat=Latitude-Radiuslat; DoubleMaxlat=Latitude+Radiuslat; //Calculate LongitudeDoubleMpdlng=Degree*Math.Cos(Latitude*(PI /  the));//cosine of the latitudeDoubleDpmlng= 1 /mpdlng; DoubleRadiuslng=Dpmlng*Raidusmile; DoubleMinlng=Longitude-radiuslng; DoubleMaxlng=Longitude+radiuslng; //System.out.println ("["+minlat+", "+minlng+", "+maxlat+", "+maxlng+"]"); //min. longitude, min latitude, maximum longitude, maximum latitudereturnNewDouble[]{minlng, Minlat, MAXLNG, Maxlat}; #endregion #region calculates the distance between two points, in meters, based on the latitude and longitude coordinates (double value) between two points/// <Summary>        ///calculates the distance between two points, in meters, based on the latitude-longitude coordinate of two points (double value)/// </Summary>        /// <param name="Lng1">Longitude 1</Param>        /// <param name="LAT1">Latitude 1</Param>        /// <param name="Lng2">Longitude 2</Param>        /// <param name="Lat2">Latitude 2</Param>        /// <returns>return distance (m)</returns>         Public DoubleGetdistance (DoubleLng1,DoubleLAT1,DoubleLng2,Doublelat2) {            DoubleRadLat1=Lat1*RAD;// //Rad=Pi/ the            DoubleRadLat2=Lat2*RAD; DoubleA=RadLat1-RadLat2; DoubleB=(lng1-LNG2)*RAD; DoubleS= 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; returns; } #endregion #endregion

SQL: Calculates the distance between two coordinate points (longitude, latitude) on the earth from the SQL function (Note: The units here are kilometers)

Go   --calculates the distance between two coordinate points (longitude, latitude) of the Earth SQL function CREATE FUNCTION [dbo].[fngetdistance](@LatBegin REAL,@LngBegin REAL,@LatEnd REAL,@LngEnd REAL)RETURNS FLOAT     as  BEGIN    --distance (km)  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 Transfer from: http://www.aspbc.com/tech/showtech.asp?id=1136
Baidu map get distance between two points online test: Http://developer.baidu.com/map/jsdemo.htm#a6_1

Calculate the distance between geographic locations