[R] maptools sunrise sunset function

Sebastian P. Luque spluque at gmail.com
Mon Nov 10 22:25:46 CET 2008

On Mon, 10 Nov 2008 15:27:52 -0500,
"stephen sefick" <ssefick at gmail.com> wrote:

> 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)
> }

> I believe that he is refering to the code that I wrote above, which
> relies heavily on map tools (to say the least).

So what's the problem?  You specified timezone="UTC" so that's what
you're getting.  WRT the warnings I do not get them, but the string
passed may be wrong or some definitions as missing from his system.
Sorry I cannot help with that.


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