[OSM-dev] Request for PHP programmers for TWISST project

[David James]

  On 01/10/2010 17:14, andrzej zaborowski wrote:
> On 1 October 2010 18:12, andrzej zaborowski<balrogg at gmail.com>  wrote:
>> Checking if a point is inside a polygons is trivial, but is it what
>> they really want?  Wouldn't just the longitude tell you the time
>> better than the timezone?
>>
>> E.g. offset_from_gmt = ((lon - 180) / 15) hours
> oops, rather (lon / 15) hours

Timezone boundaries do not exactly follow lines of longitude (Google 
finds a nice map here: http://www.travel.com.hk/region/timezone.htm).

Also there are some places where the civil time is offset from UTC by 
some hours and a half-hour and even some places where the offset has +/- 
15 minutes in it (Nepal is UTC+5 3/4).

-- 
David James
david at djames.org.uk