maybe I am wrong, but I think
SUNFUNCS_RET_TIMESTAMP return GMT(0) time
SUNFUNCS_RET_STRING Return local time
SUNFUNCS_RET_DOUBLE Return local time
(PHP 5, PHP 7)
date_sunset — Returns time of sunset for a given day and location
$timestamp
[, int $format
= SUNFUNCS_RET_STRING
[, float $latitude
= ini_get("date.default_latitude")
[, float $longitude
= ini_get("date.default_longitude")
[, float $zenith
= ini_get("date.sunset_zenith")
[, float $gmt_offset
= 0
]]]]] ) : mixed
date_sunset() returns the sunset time for a given
day (specified as a timestamp
) and location.
timestamp
The timestamp
of the day from which the sunset
time is taken.
format
constant | description | example |
---|---|---|
SUNFUNCS_RET_STRING | returns the result as string | 16:46 |
SUNFUNCS_RET_DOUBLE | returns the result as float | 16.78243132 |
SUNFUNCS_RET_TIMESTAMP | returns the result as integer (timestamp) | 1095034606 |
latitude
Defaults to North, pass in a negative value for South. See also: date.default_latitude
longitude
Defaults to East, pass in a negative value for West. See also: date.default_longitude
zenith
zenith
is the angle between the center of the sun
and a line perpendicular to earth's surface. It defaults to
date.sunset_zenith
Angle | Description |
---|---|
90°50' | Sunset: the point where the sun becomes invisible. |
96° | Civil twilight: conventionally used to signify the end of dusk. |
102° | Nautical twilight: the point at which the horizon ends being visible at sea. |
108° | Astronomical twilight: the point at which the sun ends being the source of any illumination. |
gmtoffset
Specified in hours.
The gmtoffset
is ignored, if
format
is
SUNFUNCS_RET_TIMESTAMP
.
Every call to a date/time function will generate a E_NOTICE
if the time zone is not valid, and/or a E_STRICT
or E_WARNING
message
if using the system settings or the TZ environment
variable. See also date_default_timezone_set()
Version | Description |
---|---|
5.1.0 |
Now issues the |
Returns the sunset time in a specified format
on
success or FALSE
on failure. One potential reason for failure is that the
sun does not set at all, which happens inside the polar circles for part of
the year.
Example #1 date_sunset() example
<?php
/* calculate the sunset time for Lisbon, Portugal
Latitude: 38.4 North
Longitude: 9 West
Zenith ~= 90
offset: +1 GMT
*/
echo date("D M d Y"). ', sunset time : ' .date_sunset(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1);
?>
The above example will output something similar to:
Mon Dec 20 2004, sunset time : 18:13
Example #2 No sunset
<?php
$solstice = strtotime('2017-12-21');
var_dump(date_sunset($solstice, SUNFUNCS_RET_STRING, 69.245833, -53.537222));
?>
The above example will output:
bool(false)
maybe I am wrong, but I think
SUNFUNCS_RET_TIMESTAMP return GMT(0) time
SUNFUNCS_RET_STRING Return local time
SUNFUNCS_RET_DOUBLE Return local time
yes SUNFUNCS_RET_TIMESTAMP does return GMT(0) time
so something like...
$arr = localtime(date_sunset(time(),SUNFUNCS_RET_TIMESTAMP,51.5,0)); // London
$hh = $arr[2];
$mm = $arr[1];
Will give figure out your localtime and daylight saving (BST)
I use an IP to location database to determine the visitor's approximate latitude and longitude and then serve them a day or night color scheme based on whether it is before civil dawn or dusk. I've had problems when not specifying the timezone, specifically a 1 hour error, so I use GMT.
<?php
date_default_timezone_set("GMT");
function scheme() {
$sunrise = date_sunrise(time(), SUNFUNCS_RET_DOUBLE, $latitude, $longitude, 96, 0);
$sunset = date_sunset(time(), SUNFUNCS_RET_DOUBLE, $latitude, $longitude, 96, 0);
$now = date("H") + date("i") / 60 + date("s") / 3600;
if ($sunrise < $sunset)
if (($now > $sunrise) && ($now < $sunset)) return "day";
else return "night";
else
if (($now > $sunrise) || ($now < $sunset)) return "day";
else return "night";
}
?>