CREATE FUNCTION [dbo].[CalculateDistance]
    (@Longitude1 DECIMAL(8,5), 
    @Latitude1   DECIMAL(8,5),
    @Longitude2  DECIMAL(8,5),
    @Latitude2   DECIMAL(8,5))
RETURNS FLOAT
AS
BEGIN
DECLARE @Temp FLOAT
 
SET @Temp = SIN(@Latitude1/57.2957795130823) * SIN(@Latitude2/57.2957795130823) +
 COS(@Latitude1/57.2957795130823) * COS(@Latitude2/57.2957795130823) * COS(@Longitude2/57.2957795130823 - @Longitude1/57.2957795130823)
 
IF @Temp > 1 
    SET @Temp = 1
ELSE IF @Temp < -1
    SET @Temp = -1
 
RETURN (3958.75586574 * ACOS(@Temp) ) 
 
END

from the blog I mentioned.

>>I think you can replace 4*((4*atn(1/5))-(atn(1/239))) by PI()
>>
>>And if you store the Latitude and Longitude in radians, then it becomes
>>

>>SET XAxis = cos([TABLENAME].Latitude) * cos([TABLENAME].Longitude)
>>
>>
>>likewise
>>SET YAxis = cos([TABLENAME].Latitude) * sin([TABLENAME].Longitude)
>>SET ZAxis = sin([TABLENAME].Latitude)
>>
>>

>
>Thanks
>
>I just want to verify that part. My code to replace those values are as follow:
>
>

>UPDATE test SET XAxis = (cos(((PI())/180)*Latitude)*cos(((PI())/180)*Longitude))
>UPDATE test SET XAxis = (cos(((PI())/180)*Latitude)*sin(((PI())/180)*Longitude))
>UPDATE test SET ZAxis = (sin(((PI())/180)*Latitude))
>

>
>Then, applying the related code would give the image attached:
>
>

>declare @CenterLat float=47.7795
>declare @CenterLon float=-65.7191
>declare @EarthRadius float=6371 
>declare @SearchDistance float=10000
>
>declare @CntXAxis float
>declare @CntYAxis float
>declare @CntZAxis float
>
>set @CntXAxis = cos(radians(@CenterLat)) * cos(radians(@CenterLon))
>set @CntYAxis = cos(radians(@CenterLat)) * sin(radians(@CenterLon))
>set @CntZAxis = sin(radians(@CenterLat))
>
>select *,  ProxDistance = @EarthRadius * acos( XAxis*@CntXAxis + YAxis*@CntYAxis + ZAxis*@CntZAxis)
>from test
>where  @EarthRadius * acos( XAxis*@CntXAxis + YAxis*@CntYAxis + ZAxis*@CntZAxis) <= @SearchDistance
>order by ProxDistance ASC
>

>
>The code works, but the distance calculated is enormous. There is only about 12 to 16 km between those two coordinates.