function yyyydoy_2_doy, yyyydoy

;------------------------------------------------------------------------------------------------
; 
; Input:
;   yyyydoy.....date as year & day of year (e.g., 2007212), scalar or vector
;
; Output:
;   doy.........day of year
;
; Source: Mark Hervig
;------------------------------------------------------------------------------------------------

   yy  = long(yyyydoy / 1000)
   
   doy = long( yyyydoy - yy*1000. )
       
;- done

   return, doy
   end