I have looked at ?as.POSIXct ?POSIXct and many of the references that are on those pages.
I am bewildered with timezones. Is there a way to get what would go into tz="" for making a function that uses POSIXct to be able to be used in all of the timezones in just the united states? This is for both windows and mac... this is the function that I am wanting to use it with library(maptools) sunrise.set <- function(lat, long, date, timezone="UTC", num.days=1){ #this needs to be long lat# lat.long <- matrix(c(long, lat), nrow=1) day <- as.POSIXct(date, tz=timezone) sequence <- seq(from=day, length.out=num.days , by="days") sunrise <- sunriset(lat.long, sequence, direction="sunrise", POSIXct=TRUE) sunset <- sunriset(lat.long, sequence, direction="sunset", POSIXct=TRUE) ss <- data.frame(sunrise, sunset) ss <- ss[,-c(1,3)] colnames(ss)<-c("sunrise", "sunset") return(ss) } thanks in advance, -- Stephen Sefick Research Scientist Southeastern Natural Sciences Academy Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.