unixtojd

(PHP 4, PHP 5)

unixtojd — Konvertiert Unix-Timestamp in Julianisches Datum

Beschreibung

int unixtojd ([ int $timestamp = time() ] )

Diese Funktion konvertiert den in timestamp übergebenen Wert (in Sekunden seit dem 1.1.1970) in das entsprechende Julianische Datum. Wird kein timestamp übergeben, so wird das Julianische Datum des aktuellen Tages zurückgegeben.

Parameter-Liste

timestamp: Ein zu konvertierender Unix Timestamp.

Rückgabewerte

Ein Julianischer Tag als Integer.

Siehe auch

jdtounix() - Konvertiert Julianisches Datum in Unix-Timestamp

Datum/Uhrzeit

juliantojd

[edit] Last updated: Fri, 18 May 2012

add a note User Contributed Notes unixtojd

Anonymous 20-Mar-2012 09:01


Since upgrading from PHP 5.2.9 to 5.3.10, PHP is throwing the error:



... PHP Fatal error:  Call to undefined function unixtojd() in .../unixtojd.php on line 5



Checking phpinfo(), I can see that the calendar lib is enabled:

'--enable-calendar=shared' 



Searching on Google for posts since the first release of PHP 5.3 (June 30, 2009) did not reveal much more: http://goo.gl/2YbWj



If anyone has an answer, please notify me at lsiden at gmail since I have not found a way to get notified here.



Thank you!

hrabi at linuxwaves dot com 29-Mar-2007 06:02


according to http://www.decimaltime.hynes.net/dates.html#jd and reading "X. Calendar Functions" on this side, it seems that php "jd" is precisely mean as "Chronological Julian Day" (should it be named cjd, and primarily strictly mentioned - isn't it?), used for covnersion between calendar systems. Than it's ok (but Incomplete manual is strongly confusing here IMHO).

Even that, cJD is adjusted to a local time, so... I am rather babeled now, so nothing else :-).

hrabi at linuxwaves dot com 29-Mar-2007 03:33


This is unusable. Julian Day start at noon, not midnight. It's better to use Fabio solution (however there is a lurk problem with leap second).



<?php

function mmd($txt, $str_time) {

   $t = strtotime($str_time);

   $j = unixtojd($t);

   $s = gmstrftime('%D %T %Z', $t);

   $j_fabio = $t / 86400 + 2440587.5;



   printf("${txt} => (%s) %s, %s U, %s J, or %s J<br>\n", $str_time, $s, $t, $j, $j_fabio);

}



//$xt = strtotime("1.1.1970 15:00.00 GMT");

$sam = "9.10.1995 02:00.01 GMT";

$spm = "9.10.1995 22:00.01 GMT";



// unixtojd for $spm returns 2450000 (OK), but for $sam returns 2450000 too! (it is wrong).

mmd("am", $sam);  // should be 2449999 (+ 0.58334)

mmd("pm", $spm);  // should be 2450000 (+ 0.41668)

?>



reference

unix time, and UTC, TAI, ntp, ... problems: http://en.wikipedia.org/wiki/Unix_time

Julian Date Converter: http://aa.usno.navy.mil/data/docs/JulianDate.html

history overview: http://parris.josh.com.au/humour/work/17Nov1858.shtml

fabio at llgp dot org 31-Aug-2006 02:09


If you need an easy way to convert an unix timestamp to a decimal julian day you can use:



$julianDay = $unixTimeStamp / 86400 + 2440587.5;



86400 is the number of seconds in a day;

2440587.5 is the julian day at 1/1/1970 0:00 UTC.

10-Aug-2006 07:22


Its clearly stated that this function returns the Julian Day, not Julian Day + time.



If you want the time with it you will have to do something like:



$t=time();

$jd=unixtojd($t)+($t%60*60*24)/60*60*24;

johnston at capsaicin dot ca 19-Nov-2003 01:43


Also note that epoch is in UTC time (epoch is a specific point in time - epoch is not different for every time zone), so be aware of timezone complexities.

pipian at pipian dot com 12-Jun-2003 09:29


Remember that UNIX timestamps indicate a number of seconds from midnight of January 1, 1970 on the Gregorian calendar, not the Julian Calendar.

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