search for: sunriset

...RM61 <- matrix(c(-81.262388, 32.524739), nrow=1) RM215.sp <- SpatialPoints(RM215, proj4string=CRS("+proj=longlat +datum=WGS84")) d060101 <- as.POSIXct("2006-01-01", tz="EST") study_seq <- seq(from=d060101, length.out=761, by="days") up.215 <- sunriset(RM215.sp, study_seq, direction="sunrise", POSIXct.out=TRUE) down.215 <- sunriset(RM215.sp, study_seq, direction="sunset", POSIXct.out=TRUE) SC.sp <- SpatialPoints(SC, proj4string=CRS("+proj=longlat +datum=WGS84")) up.SC <- sunriset(SC.sp, study_seq, direction...

Hi ... I wonder if anyone can provide some insight into why the first three examples using the sunriset function (appended below, with results) give the correct answer, but the fourth generates and error. The first two use ISOdatetime with and without a time zone attribute, and the sunriset function returns the correct sunset time. The third and fourth adds 10 seconds to the ISOdatetime (with and...

...lues for the first day of change. The time change is Nov 6,2011. The value for Nov 7 turns into 23:00 on Nov 6, thus two values for Nov 6. (see below) So I put a time value (noon) into the sequence, that did give me a correct date sequence. 2. When using that modified date sequence in maptools::sunriset(), on day of change to stardard time the sunrise time is shifted by one hour. (i.e. Nov5 8am, Nov6 6am, Nov7 7am) I can't fathom why sunriset() is giving me funny results on the day of time change. I wonder if there is something amiss with how my windows XP is managing time zones perhaps? I wo...

RM215.sp <- SpatialPoints(RM215, proj4string=CRS("+proj=longlat +datum=WGS84")) d060101 <- as.POSIXct("2006-01-01", tz="EST") study_seq <- seq(from=d060101, length.out=761, by="days") up.215 <- sunriset(RM215.sp, study_seq, direction="sunrise", POSIXct.out=TRUE) down.215 <- sunriset(RM215.sp, study_seq, direction="sunset", POSIXct.out=TRUE) #I would like to extract just the time part of the output is there any way to do this? -- Let's not spend our time and resources...

...ary(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) } #This does...

...- 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")...

Are there any functions available to calculate sunrise and sunset times for given latitude,longitude and dates? If not, I'll appreciatte any pointers to C code I could use/port. Thanks, Angel

Hello, I'm having problems working with date values in POSIXct format. Here is what I got (eg.lig attached): x <- read.table("eg.txt", sep = ',', col.names=c("ok","time","secs","lig")) # it gives time as factor z <- cbind(x,colsplit(x$time, split="\\s", names=c("date", "clock")))

hi there, does anyone know how to calculate the amount of daylight on every day of the year in R? I mean the time between sunrise and sunset. thanks -- View this message in context: http://r.789695.n4.nabble.com/daylight-tp4647213.html Sent from the R help mailing list archive at Nabble.com.