date_sub
We needed the length of the day, both sunrise to sunset and twilight to twilight for particular latitudes. Sun_info() is just the thing. We mistakenly thought 'transit' was this value, which it is not. Transit is the time of day the sun is at its zenith. To get length of day, one must perform math on the results of sun_info().
When doing math with time values, don't expect date() to do the conversion to hours:minutes:seconds. date() thinks the passed value is a time since the epoch. You will need to do your own conversion to hours:minutes:seconds, using something like the following:
<?php
function hms($val) {
// convert seconds to hours:minutes:seconds
$v=$val;
$h=intval($v/3600);
$v-=($h*3600); // subtract hours
$m=intval($v/60);
$v-=($m*60); // subtract minutes
$s=$v % 60; // seconds remaining
if ($h<10) {$h="0".$h;}
if ($m<10) {$m="0".$m;}
if ($s<10) {$s="0".$s;}
return $h.":".$m.":".$s;
}
?>
Regarding date_sunrise() and date_sunset(), these both return values without seconds and without correction for Daylight time. Whereas sun_info() handles seconds as well as Daylight time. It even handles dates prior to the epoch correctly as negative timestamps, at least as of php 5.2.12
For example,
sun_info(strtotime('July 4, 1776'),47.3506,-122.6417)
produces something like the following when using date_default_timezone_set('America/Los_Angeles') and
date("H:i:s", $val)
sunrise: 04:20:26 [-6106016374]
sunset: 20:09:03 [-6105959457]
transit: 12:14:45 [-6105987915]
civil_twilight_begin: 03:40:54 [-6106018746]
civil_twilight_end: 20:48:35 [-6105957085]
nautical_twilight_begin: 02:46:58 [-6106021982]
nautical_twilight_end: 21:42:31 [-6105953849]
astronomical_twilight_begin: 01:28:06 [-6106026714]
astronomical_twilight_end: 23:01:23 [-6105949117]
* * *
date_sun_info
(PHP 5 >= 5.1.2)
date_sun_info — Retorna um array com informações sobre pôr-do-sol/nascer-do-sol e o início/fim do dia
Descrição
array date_sun_info
( int $time
, float $latitude
, float $longitude
)
Parâmetros
- time
-
Timestamp.
- latitude
-
Latitude em graus.
- longitude
-
Longitude em graus.
Valor Retornado
Retorna um array em caso de sucesso ou FALSE em caso de falha.
Exemplos
Exemplo #1 Um exemplo de date_sun_info()
<?php
$sun_info = date_sun_info(strtotime("2006-12-12"), 31.7667, 35.2333);
foreach ($sun_info as $key => $val) {
echo "$key: " . date("H:i:s", $val) . "\n";
}
?>
O exemplo acima irá imprimir:
sunrise: 05:52:11 sunset: 15:41:21 transit: 10:46:46 civil_twilight_begin: 05:24:08 civil_twilight_end: 16:09:24 nautical_twilight_begin: 04:52:25 nautical_twilight_end: 16:41:06 astronomical_twilight_begin: 04:21:32 astronomical_twilight_end: 17:12:00
Veja Também
- date_sunrise() - Returns time of sunrise for a given day and location
- date_sunset() - Returns time of sunset for a given day and location
User Contributed Notes
date_sun_info
date_sun_info
mother at localsnow dot com
23-Jun-2010 06:55
23-Jun-2010 06:55
glenbo (_AT_) mac (_DOT_) com
17-Jun-2008 04:54
17-Jun-2008 04:54
It should be noted that for extreme geographical locations date_sun_info() might return unexpected values. Values of 1 or empty may be returned. If you are expecting a unix timestamp this will default to the epoch, or epoch+1, which is not what you would expect.
After researching official almanac records for these locations it appears likely that for sunrise and sunset return values of 1 relate to a situation where the sun is above the horizon for the entire 24 hour day. It is also possible that empty return values relate to a situation where the sun is below the horizon for the entire 24 hour day. In the case of twilight data a 1 probably means that the sun never dips below that zenith, and an empty value means the sun never rises above said zenith for that given day.
The following code exhibits unique dates from the northernmost city Ny-Ålesund, Svalbard, and the southernmost city McMurdo Research Station, Antarctica.
<?php
$northernmost_city_latitude = 78.92; // Ny-Ålesund, Svalbard
$northernmost_city_longitude = 11.93;
$southernmost_city_latitude = -77.88; // McMurdo Research Station, Antarctica
$southernmost_city_longitude = 166.73;
print_r( date_sun_info( strtotime("2008-01-01") , $northernmost_city_latitude, $northernmost_city_longitude) );
print_r( date_sun_info( strtotime("2008-04-01") , $northernmost_city_latitude, $northernmost_city_longitude) );
print_r( date_sun_info( strtotime("2008-01-01") , $southernmost_city_latitude, $southernmost_city_longitude) );
print_r( date_sun_info( strtotime("2008-06-01") , $southernmost_city_latitude, $southernmost_city_longitude) );
?>
This will return the following. Observe that sometimes a value of 1 or empty is returned.
Array
(
[sunrise] =>
[sunset] =>
[transit] => 1199186158
[civil_twilight_begin] =>
[civil_twilight_end] =>
[nautical_twilight_begin] => 1199184075
[nautical_twilight_end] => 1199188241
[astronomical_twilight_begin] => 1199170475
[astronomical_twilight_end] => 1199201840
)
Array
(
[sunrise] => 1207019232
[sunset] => 1207077865
[transit] => 1207048548
[civil_twilight_begin] => 1
[civil_twilight_end] => 1
[nautical_twilight_begin] => 1
[nautical_twilight_end] => 1
[astronomical_twilight_begin] => 1
[astronomical_twilight_end] => 1
)
Array
(
[sunrise] => 1
[sunset] => 1
[transit] => 1199148994
[civil_twilight_begin] => 1
[civil_twilight_end] => 1
[nautical_twilight_begin] => 1
[nautical_twilight_end] => 1
[astronomical_twilight_begin] => 1
[astronomical_twilight_end] => 1
)
Array
(
[sunrise] =>
[sunset] =>
[transit] => 1212281461
[civil_twilight_begin] =>
[civil_twilight_end] =>
[nautical_twilight_begin] => 1212273312
[nautical_twilight_end] => 1212289609
[astronomical_twilight_begin] => 1212264187
[astronomical_twilight_end] => 1212298734
)