Calculating distance between two points (Latitude, Longitude)
Since you're using SQL Server 2008, you have the geography
data type available, which is designed for exactly this kind of data:
DECLARE @source geography = 'POINT(0 51.5)'
DECLARE @target geography = 'POINT(-3 56)'
SELECT @source.STDistance(@target)
Gives
----------------------
538404.100197555
(1 row(s) affected)
Telling us it is about 538 km from (near) London to (near) Edinburgh.
Naturally there will be an amount of learning to do first, but once you know it it's far far easier than implementing your own Haversine calculation; plus you get a LOT of functionality.
If you want to retain your existing data structure, you can still use STDistance
, by constructing suitable geography
instances using the Point
method:
DECLARE @orig_lat DECIMAL(12, 9)
DECLARE @orig_lng DECIMAL(12, 9)
SET @orig_lat=53.381538 set @orig_lng=-1.463526
DECLARE @orig geography = geography::Point(@orig_lat, @orig_lng, 4326);
SELECT *,
@orig.STDistance(geography::Point(dest.Latitude, dest.Longitude, 4326))
AS distance
--INTO #includeDistances
FROM #orig dest
The below function gives distance between two geocoordinates in miles
create function [dbo].[fnCalcDistanceMiles] (@Lat1 decimal(8,4), @Long1 decimal(8,4), @Lat2 decimal(8,4), @Long2 decimal(8,4))
returns decimal (8,4) as
begin
declare @d decimal(28,10)
-- Convert to radians
set @Lat1 = @Lat1 / 57.2958
set @Long1 = @Long1 / 57.2958
set @Lat2 = @Lat2 / 57.2958
set @Long2 = @Long2 / 57.2958
-- Calc distance
set @d = (Sin(@Lat1) * Sin(@Lat2)) + (Cos(@Lat1) * Cos(@Lat2) * Cos(@Long2 - @Long1))
-- Convert to miles
if @d <> 0
begin
set @d = 3958.75 * Atan(Sqrt(1 - power(@d, 2)) / @d);
end
return @d
end
The below function gives distance between two geocoordinates in kilometres
CREATE FUNCTION dbo.fnCalcDistanceKM(@lat1 FLOAT, @lat2 FLOAT, @lon1 FLOAT, @lon2 FLOAT)
RETURNS FLOAT
AS
BEGIN
RETURN ACOS(SIN(PI()*@lat1/180.0)*SIN(PI()*@lat2/180.0)+COS(PI()*@lat1/180.0)*COS(PI()*@lat2/180.0)*COS(PI()*@lon2/180.0-PI()*@lon1/180.0))*6371
END
The below function gives distance between two geocoordinates in kilometres using Geography data type which was introduced in sql server 2008
DECLARE @g geography;
DECLARE @h geography;
SET @g = geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326);
SET @h = geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326);
SELECT @g.STDistance(@h);
Usage:
select [dbo].[fnCalcDistanceKM](13.077085,80.262675,13.065701,80.258916)
Reference: Ref1,Ref2