pw_images, UTC, TimeZones, LocalTime

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

To make pw_images display the correct (day or night) icon, for the 
moment I've hacked up get_sky_image() as follows

/* hacked for Sydney, Summer Time, Phil Pierotti, 04-01-03 */

  $metarDST_start = '10310200'; // MMddhhmm
  $metarDST_end = '03280300';
  $metarGMTOffset = 10 ;
  $metarUsesDST = 1;
  $metarSunRise = 6;
  $metarSunSet = 20;

  if($metarUsesDST) {
  	$todayCheck = date('mdHi');
  	if(($todayCheck >= $metarDST_start)  && ($todayCheck < $metarDST_end)) {
  		$metarDSTOffset = 1;
  	}
  } else {
  	$metarDSTOffset = 0;
  }

  $metarTime = ($regs[2] + $metarGMTOffset + $metarDSTOffset) % 24;

  if (($metarTime > $metarSunSet) || ($metarTime < $metarSunRise)) {

/* ------- */         	


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

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


Enjoy,
Phil P