date_sub
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
)
date_sun_info
(PHP 5 >= 5.1.2)
date_sun_info — 日の出/日の入り時刻と薄明かり (twilight) の開始/終了時刻の情報を含む配列を返す
説明
array date_sun_info
( int $time
, float $latitude
, float $longitude
)
パラメータ
- time
-
タイムスタンプ。
- latitude
-
緯度を表す度数。
- longitude
-
経度を表す度数。
返り値
成功した場合に配列、失敗した場合に FALSE を返します。
例
例1 date_sun_info() の例
<?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";
}
?>
上の例の出力は以下となります。
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
add a note
User Contributed Notesdate_sun_info
glenbo (_AT_) mac (_DOT_) com
17-Jun-2008 07:54
17-Jun-2008 07:54