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DistanceBetween ( double Lat1, double Long1, double Lat2, double Long2 ) : double |
C# Replacement for Stored Procedure CREATE FUNCTION [dbo].[DistanceBetween] (@Lat1 as real, @Long1 as real, @Lat2 as real, @Long2 as real) RETURNS real AS BEGIN DECLARE @dLat1InRad as float(53); SET @dLat1InRad = @Lat1 * (PI()/180.0); DECLARE @dLong1InRad as float(53); SET @dLong1InRad = @Long1 * (PI()/180.0); DECLARE @dLat2InRad as float(53); SET @dLat2InRad = @Lat2 * (PI()/180.0); DECLARE @dLong2InRad as float(53); SET @dLong2InRad = @Long2 * (PI()/180.0); DECLARE @dLongitude as float(53); SET @dLongitude = @dLong2InRad - @dLong1InRad; DECLARE @dLatitude as float(53); SET @dLatitude = @dLat2InRad - @dLat1InRad; * Intermediate result a. */ DECLARE @a as float(53); SET @a = SQUARE (SIN (@dLatitude / 2.0)) + COS (@dLat1InRad) * COS (@dLat2InRad) * SQUARE(SIN (@dLongitude / 2.0)); * Intermediate result c (great circle distance in Radians). */ DECLARE @c as real; SET @c = 2.0 * ATN2 (SQRT (@a), SQRT (1.0 - @a)); DECLARE @kEarthRadius as real; * SET kEarthRadius = 3956.0 miles */ SET @kEarthRadius = 6376.5; /* kms */ DECLARE @dDistance as real; SET @dDistance = @kEarthRadius * @c; return (@dDistance); END |
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