Re: pw_images, UTC, TimeZones, LocalTime

[Phil P. <phi...@sw...>]

A little trolling around on the web found me THIS interesting chunk of 
PHP code:

http://www.zend.com/codex.php?id=135&single=1

Specificallly, an implementation of calculating sunrise and set from 
LAT+LONG+GMT Offset

Enjoy,
Phil P


Martin Geisler wrote:

> Phil Pierotti <phi...@sw...> writes:
> 
> 
>>Realistically, for this to be complete and flexible, each ICAO will
>>need the following information:
>>	- TimeZone specified as offset from GMT
>>	- uses Daylight Savings?
>>	- DST start date
>>	- DST end date
>>	- latitude & longitude
>>
>>The sunrise and sunset times can be calculated from the information
>>from NOAA http://www.srrb.noaa.gov/highlights/sunrise/calcdetails.html
> 
> 
> Thanks a lot for that link --- we've made an attempt to implement this
> kind of functionality before, but when I searched the net I only found
> some messy algorithms that I didn't have much luck with, see
> 
>   http://makeashorterlink.com/?T162215A2
> 
> The information on the above page looks much clearer, and it should be
> easy to port the JavaScript code to PHP --- those two languages are
> very much alike.
> 
> 
>>Lat and Long can be had for ICAOs from
>>http://weather.noaa.gov/tg/site.shtml directly ->
>>http://weather.noaa.gov/data/nsd_cccc.txt
> 
> 
> Thanks again --- I've found those datafiles before, but the
> information is still not part of PHP Weather.  Given the latitude and
> longitude it should be possible to calculate an approximate timezone.
> 
> And with that timezone we should be able to give a local time for the
> reports, but I guess it will still be off by +/- 1 hours depending on
> daylight saving time, so I don't know how good that idea is.
> 
> It's just that the real solution: attaching detailed information about
> the daylight saving time to each station, sounds like a difficult
> task.  But then again, there must be some tables with this information
> somewhere on every system, so perhaps it's doable?
> 
> 
> In any case --- I'm having my exams right now!  The first one will be
> on Wednesday, so I wont start playing with this stuff now, but if
> someone else feels like it, then by all mean do!  I can add people to
> the project as developers if they believe they need CVS access.
>