Archive for March, 2009
Google Latitude
by admin on Mar.11, 2009, under Misc Items
Recently Google released a new service named Latitude. Very simly it takes your location from mobile device or online using iGoogle and Gears and plots it on a map. From there you can share your current location with friends and contacts who also use google latitude. There are a number of privacy options on the service; set who and how you want to share location or the option to set a specific location too.
Not sure how much I’ll be using this or a service like Latitude but its interesting to discover and see how it works.
Haversine Distance in Miles with TSQL Latitude Longitude
by admin on Mar.05, 2009, under Misc Items
A little non-multimedia post coming your way … a little bit of TSQL goodness for calculating the distance between two latitude and longitude coordinates.
SET ANSI_NULLS OFF
GO
SET QUOTED_IDENTIFIER OFF
GO
CREATE FUNCTION [dbo].[HaversineDistanceMiles] (
@lat1 float,
@lon1 float,
@lat2 float,
@lon2 float
)
RETURNS float AS
BEGIN
declare @dlon float
declare @dlat float
declare @a float
declare @c float
declare @d float
select @dlon=radians(@lon2)-radians(@lon1)
select @dlat=radians(@lat2)-radians(@lat1)
select @a =square(sin(@dlat/2.0)) + (cos(radians(@lat1)) * cos(radians(@lat2)) * square(sin(@dlon/2.0)))
select @c = 2.0 * atn2(sqrt(@a), sqrt(1.0-@a))
select @d = 3956 * @c
return @d
END
