lat/lon to time offset database

Clive D.W. Feather clive at
Thu Feb 3 20:10:26 UTC 2011

John Haxby said:
>> I am looking at building a small embedded system (No OS) that will require 
>> determining the local time from the lat/lon of a location. So basically I need 
>> lat/lon to time offset from "GMT".
> Does that work?

Well, yes, if you have a detailed enough set of polygons. But that's the
difficult bit.

>  Also, when you're on going through the channel tunnel do you go from being closer to Paris than you are to London only when you've left Calais?  Or before you get to Dover?

By rail the distance is 491.5 km. The tunnel portals are 162.05 (France)
and 111.60 (UK) km from London. The 245.75 point is just west of the
Erquinghem crossovers near Armentieres, about 21.4km west of Lille station.

Clive D.W. Feather          | If you lie to the compiler,
Email: clive at     | it will get its revenge.
Web:  |   - Henry Spencer
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