SQLSERVER地図の経緯度から距離差を計算する例

 
go 
--            
CREATEFUNCTION [dbo].[fnGetDistance] 
--LatBegin      
--LngBegin      
(@LatBegin REAL, @LngBegin REAL, @LatEnd REAL, @LngEnd REAL) 
RETURNSFLOAT 
AS 
BEGIN 
--  (  ) 
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 

@Distance    :