Calculating Distance based on Lat/Long Coordinates

A friend of mine wrote this script for some reason and forwarded to me for the heck of it! I have no use for it but figured somebody else might be looking for it! So here it is... If you have any questions, feel free to post 'em and I will run it by Narayan.

-- =============================================

-- Author:

-- Create date: <24/04/2009>

-- Description:

-- =============================================

CREATE FUNCTION [dbo].[udfLatLonRadiusDistance]

(

@lat1Degrees decimal(15,12),

@lon1Degrees decimal(15,12),

@lat2Degrees decimal(15,12),

@lon2Degrees decimal(15,12)

)

RETURNS decimal(9,2)

AS

BEGIN

DECLARE @earthSphereRadiusNauticalMiles as decimal(10,6)

DECLARE @nauticalMileConversionToMilesFactor as decimal(7,6)

SELECT @earthSphereRadiusNauticalMiles = 6366.707019

SELECT @nauticalMileConversionToMilesFactor = .621371

-- convert degrees to radians

DECLARE @lat1Radians decimal(15,12)

DECLARE @lon1Radians decimal(15,12)

DECLARE @lat2Radians decimal(15,12)

DECLARE @lon2Radians decimal(15,12)

SELECT @lat1Radians = (@lat1Degrees / 180) * PI()

SELECT @lon1Radians = (@lon1Degrees / 180) * PI()

SELECT @lat2Radians = (@lat2Degrees / 180) * PI()

SELECT @lon2Radians = (@lon2Degrees / 180) * PI()

-- formula for distance from [lat1,lon1] to [lat2,lon2]

RETURN ROUND(2 * ASIN(SQRT(POWER(SIN((@lat1Radians - @lat2Radians) / 2) ,2)

+ COS(@lat1Radians) * COS(@lat2Radians) * POWER(SIN((@lon1Radians - @lon2Radians) / 2), 2)))

* (@earthSphereRadiusNauticalMiles * @nauticalMileConversionToMilesFactor), 4)

END

Please consider the environment before printing this blog! Go Green!








Credit for this idea goes to http://blogs.msdn.com/chrishays/archive/2004/08/30/GreenBarMatrix.aspx