CREATE FUNCTION [dbo].[Rad](

@d float

)

 RETURNS float

BEGIN

  return @d * PI()/ 180.00;

 End

CREATE FUNCTION [dbo].[DISTANCE](

@lat1 float,

@lng1 float,

@lat2 float,

@lng2 float

)

 RETURNS float

BEGIN

  Declare @radLat1 float,@radLat2 float,

		  @radLon1 float,@radLon2 float,

		  @x1 float,@x2 float,

		  @y1 float,@y2 float,

		  @z1 float,@z2 float,

		  @d float,@theta float,@dist float,

		  @EARTH_RADIUS float = 6378.137;

  set @radLat1 = dbo.Rad(@lat1);

  set @radLat2 = dbo.Rad(@lat2);

  set @radLon1=dbo.Rad(@lng1);

  set @radLon2=dbo.Rad(@lng2);

  if @radLat1<0

	set @radLat1 = PI() / 2 + ABS(@radLat1);-- south

  if @radLat1>0

     set @radLat1 = PI() / 2 - ABS(@radLat1);-- north

  if @radLon1<0

     set @radLon1 = PI() * 2 - ABS(@radLon1);-- west

  if @radLat2<0

      set @radLat2 = PI() /2 -ABS(@radLat2);-- south

  if @radLat2>0

      set @radLat2 = PI() / 2 - ABS(@radLat2);-- north

  if @radLon2<0

     set @radLon2 = PI() * 2 - ABS(@radLon2);-- west

	set @x1= @EARTH_RADIUS * COS(@radLon1) * SIN(@radLat1);

	set @y1= @EARTH_RADIUS * SIN(@radLon1) * SIN(@radLat1);

	set @z1= @EARTH_RADIUS * COS(@radLat1);

	set @x2= @EARTH_RADIUS * COS(@radLon2) * SIN(@radLat2);

	set @y2= @EARTH_RADIUS * SIN(@radLon2) * SIN(@radLat2);

	set @z2= @EARTH_RADIUS * COS(@radLat2);

	set @d= SQRT(

				  (@x1 - @x2) *

				  (@x1 - @x2) +

				  (@y1 - @y2) *

				  (@y1 - @y2) +

				  (@z1 - @z2) *

				  (@z1 - @z2)

			  );

	--余弦定理求夹角

	set @theta= ACOS((@EARTH_RADIUS * @EARTH_RADIUS + @EARTH_RADIUS * @EARTH_RADIUS - @d * @d) / (2 * @EARTH_RADIUS * @EARTH_RADIUS));

	set @dist= @theta * @EARTH_RADIUS;

  return @dist;

 End

select dbo.DISTANCE(113.52271, 22.263208, 113.520257, 22.245865)

 　　　　/// <summary>

        /// 转化为弧度(rad)

        /// </summary>

        /// <param name="d"></param>

        /// <returns></returns>

        private static double rad(double d)

        {

            return d * Math.PI / 180.0;

        }

 　　　　/// <summary>

        /// 基于余弦定理求两经纬度距离

        /// </summary>

        /// <param name="lon1">第一点的经度</param>

        /// <param name="lat1">第一点的纬度</param>

        /// <param name="lon2">第二点的经度</param>

        /// <param name="lat2">第二点的纬度</param>

        /// <returns>返回的距离，单位km </returns>

        public static double LantitudeLongitudeDist(double lon1, double lat1, double lon2, double lat2)

        {

            var EARTH_RADIUS = 6378.137;

            double radLat1 = rad(lat1);

            double radLat2 = rad(lat2);

            double radLon1 = rad(lon1);

            double radLon2 = rad(lon2);

            if (radLat1 < )

                radLat1 = Math.PI /  + Math.Abs(radLat1);// south

            if (radLat1 > )

                radLat1 = Math.PI /  - Math.Abs(radLat1);// north  

            if (radLon1 < )

                radLon1 = Math.PI *  - Math.Abs(radLon1);// west

            if (radLat2 < )

                radLat2 = Math.PI /  + Math.Abs(radLat2);// south  

            if (radLat2 > )

                radLat2 = Math.PI /  - Math.Abs(radLat2);// north

            if (radLon2 < )

                radLon2 = Math.PI *  - Math.Abs(radLon2);// west  

            double x1 = EARTH_RADIUS * Math.Cos(radLon1) * Math.Sin(radLat1);

            double y1 = EARTH_RADIUS * Math.Sin(radLon1) * Math.Sin(radLat1);

            double z1 = EARTH_RADIUS * Math.Cos(radLat1);

            double x2 = EARTH_RADIUS * Math.Cos(radLon2) * Math.Sin(radLat2);

            double y2 = EARTH_RADIUS * Math.Sin(radLon2) * Math.Sin(radLat2);

            double z2 = EARTH_RADIUS * Math.Cos(radLat2);

            double d = Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2) + (z1 - z2) * (z1 - z2));

            //余弦定理求夹角

            double theta = Math.Acos((EARTH_RADIUS * EARTH_RADIUS + EARTH_RADIUS * EARTH_RADIUS - d * d) / ( * EARTH_RADIUS * EARTH_RADIUS));

            double dist = theta * EARTH_RADIUS;

            return dist;

        }

        [TestMethod]

        public void GPS()

        {var s = LantitudeLongitudeDist(113.52271, 22.263208, 113.520257, 22.245865);

        }