timezone algorithm

[Rikard]

Hi

Looking for a function that returns the timezone for any given point.
I want to feed it with longitude and latitude.

any ideas?

 

[Jim]

Hi

Looking for a function that returns the timezone for any given point.
I want to feed it with longitude and latitude.

any ideas?

The trivial timezone algorithm is +/- 1 hour for every
15 degrees longitude, latitude doesn't really matter.

The bad news is there are very few time zones that
are that neatly arranged. See the following

http://aa.usno.navy.mil/faq/docs/world_tzones.html

As you can see, as long as you're out over water
(most of time) you're ok, but get anywhere close
to where people live........

Jim

 

[Alun Harford]

The trivial timezone algorithm is +/- 1 hour for every
15 degrees longitude, latitude doesn't really matter.

The bad news is there are very few time zones that
are that neatly arranged. See the following

http://aa.usno.navy.mil/faq/docs/world_tzones.html

As you can see, as long as you're out over water
(most of time) you're ok, but get anywhere close
to where people live........

And that doesn't take into account places that change their clocks depending
on the time of year.

Alun Harford

 

[Rhino]

And that doesn't take into account places that change their clocks depending
on the time of year.

Or who change it by unusual amounts. Although the norm is to move the clocks
ahead one hour for summer time, some areas move their clocks forward
different amounts. I've heard of two hours and even of one place that moves
their clocks only 15 minutes.

And some places don't participate in daylight savings time at all. I think
Saskatchewan is on permanent summer time - or is it "double summer time"?

Rhino