R/doyday.R

In insol: Solar Radiation

doyday <-
function(year,doy){
	if (nargs() < 1 ) {cat("USAGE: doyday(year,doy) \nUSAGE: doyday \n(year.dy)"); return()}
	fyy = floor(year)
	if (nargs() == 1 ) {
	nd = ifelse((fyy%%4==0 & fyy%%100!=0) | fyy%%400==0,366,365)
	dd = (year-fyy)*nd
	} else {
	yy = year
	dd = doy }
	fdd = floor(dd)
	hh = (dd-fdd)*24
	fhh = floor(hh)
	mm = (hh-fhh)*60
	fmm = floor(mm)
	ss = (mm-fmm)*60
	fss = floor(ss)
	return(strptime(paste(fyy,fdd,fhh,fmm,fss),format="%Y %j %H %M %S"))
}