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PHP : Function Reference : Calendar Functions : GregorianToJD

GregorianToJD

Converts a Gregorian date to Julian Day Count ()
int gregoriantojd ( int month, int day, int year )

Example 369. Calendar functions

<?php
$jd
= GregorianToJD(10, 11, 1970);
echo
"$jd\n";
$gregorian = JDToGregorian($jd);
echo
"$gregorian\n";
?>

Code Examples / Notes » gregoriantojd

jettyrat

You can obtain the decimal fraction of the Julian date with the php gregoriantojd() function or the function shown below by applying this code to the returned value.
 $julianDate = gregoriantojd($month, $day, $year);
 //correct for half-day offset
 $dayfrac = date('G') / 24 - .5;
 if ($dayfrac < 0) $dayfrac += 1;
 //now set the fraction of a day
 $frac = $dayfrac + (date('i') + date('s') / 60) / 60 / 24;
 $julianDate = $julianDate + $frac;


httpwebwitch

This function also ignores decimal fractions in JD dates, and it uses non-standard format for returning the Gregorian date.
So, if your JD date is 2453056.28673, the Gregorian returned value is 2/20/2004, not "2004-02-20 23:45:36"
The decimal part is important, since the Julian day begins at noon, for example 2453056.49 is on Friday, 2453056.50 is on Saturday. Discarding the decimal part means that your returned Gregorian Date will be wrong 50% of the time.


ryker

/*
* ComputeDateDifference(...)
*   Description:
*     Calculates the difference between two dates.
*
*   Parameter:
*     $m0, $d0, $y0   => 1. Moth/Day/Year
*     $m1, $d1, $y1   => 2. Moth/Day/Year
*
*   Return:
*     Difference between given dates in days.
*
*   Autor:
*     06.06.2006 - Christian Meyer <ryker@ridgex.net>
*/
function ComputeDateDifference($m0,$d0,$y0,$m1,$d1,$y1)
{
 $x0 = gregoriantojd($m0,$d0,$y0);
 $x1 = gregoriantojd($m1,$d1,$y1);  
 
 $diff = $x1 - $x0;
 
 if ($diff < 0)
   $diff *= -1; // abs
   
 return $diff;    
}


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