source: trunk/SRC/Calendar/date2jul.pro @ 278

;+
;
; @file_comments
; gives Julian day equivalent of a date in yyyymmdd format
;
; @categories
; Calendar
;
; @param date {in}{required} {type=string}
; date in yyyymmdd format
;
; @keyword GRADS
; if  1 <= year <= 49 --> year = 2000 + year
; if 50 <= year <= 99 --> year = 1900 + year
;
; @returns
; date in Julian day
;
; @examples
;
; IDL> jday = juldate(19930124)
; IDL> print, date2jul(19931205) EQ julday(12,5,1993)
;       1
; IDL> print, date2jul(931205,/grads) EQ julday(12,5,1993)
;       1
;
; @history
; Sebastien Masson (smasson\@lodyc.jussieu.fr) June 2005
;
; @version
; $Id$
;
;-
;
function date2jul, date, GRADS = grads
;
  compile_opt idl2, strictarrsubs
;
   year = long(date) / 10000
   month = long(abs(date)/100) MOD 100
   day = long(abs(date)) MOD 100
;------------------------------------------------------------
   if keyword_set(grads) then year = year $
     + 1900 * (year GE 50 AND year LE 99) $
     + 2000 * (year GE  1 AND year LE 49)
;------------------------------------------------------------
  IF size(date, /type) LE 3 THEN return, julday(month, day, year)

  fraction = date - long(date)
  hour = floor(fraction * 24d)
  fraction = TEMPORARY(fraction) - hour/24d
  minute = floor(fraction*1440d)
  second = (TEMPORARY(fraction) - minute/1440d) * 86400d

  return, julday(month, day, year, hour, minute, second)

end