similar to: maptools, sunriset, POSIX timezones

##This is a function that I am trying to write to calculate sunrise and sunset and works "mostly", but returns nonsensical values. What am I #missing? Thanks in advance. ###remember to include maptools as dependence### 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),

# I am sure that I could be more efficient than this but how? Thanks in advance. #GPS in Decimal Degrees in the form longitude latitude RM215 <- matrix(c(-82.1461363, 33.5959109), nrow=1) SC <- matrix(c(-82.025888, 33.606454), nrow=1) RM202 <- matrix(c(-81.9906723, 33.5027653), nrow=1) RM198 <- matrix(c(-81.926823, 33.4634678), nrow=1) HC <- matrix(c(-81.920505, 33.46192), nrow=1)

Hello all, After beating my head against the wall for a few hours, I give up. I have two problems. 1. If I use seq() to generate a POSIXct series that crosses a daylight savings to stardard time change I get two values 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)

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

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",

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.

#QUESTION# Is there a way to calculate the offset between timezones, e.g. from "AST" to "GMT"? #DETAILS# I am working with data files that use local time, and that indicate the timezone by e.g. "AST" (Atlantic Standard Time, my local time) in a header. I was guessing that > ISOdatetime(2008,1,1,1,0,0,tz="GMT") - >

Hello, I at first thought this was a system or locale issue, but since it occurs on both Windows and Linux and only for 2004 (AFAIK) I report it. I have a problem with as.POSIXct for the hour between "2004-10-03 02:00:00 GMT" and "2004-10-03 02:59:59 GMT". In short, the 2 AM (GMT) hour in 2004 (but not in other years) is interpreted as 1 AM by strptime: (I use ISOdatetime

Dear list, I need to transform the DateTime of my GPS data from: "666.1751" into "yyyy/mm/dd hh:mm:ss" I have the following code: d$Date <- ISOdatetime(2009, 1, 1, 0, 0, 0, tz = "GMT")+d$Date*(24*3600) This gives me: 2010-10-29 04:12:09, which is wrong. It should be 2010-10-29 06:12:09 Another example: 418.3219 corresponds to: 2010-02-23 07:43:30, but it

Hi All, I am watching a strange behaviour of ISOdatetime. In my work computer, I get NA when I try to do > ISOdatetime(1995,03,26,2,0,0) [1] NA But on other dates and/or times (hour) works OK > ISOdatetime(1995,03,25,2,0,0) [1] "1995-03-25 02:00:00 GMT" In my home computer, I do not have this problem. I am running the same version of R (2.8.1 patched) on both machines, the

Hi all, I am using ISOdatetime, and I just found out that when I do ISOdatetime(1995,03,26,2,10,0) (or any other value under minutes or seconds) I get NA This does not happen with the same time in other dates, nor with different hours in the same date. Any hint why this happens? Using R 2.8.1 under ESS/GnuEmacs under Windows XP Pedro -- View this message in context:

Dear R users, I have a quick question regarding creating an index for a zoo object. I am using R 2.12 on winxp. I have read through the R archives searching for information on dates and time series analysis and nothing seems to cover my question. I am extracting data from a time series of remote sensing data. The frequency of the data is 16 days which means I cant use ts (ts likes months single

Dear all, I am using the ISOdatetime function like this: test.info$TradeTime = with(test.info, mapply(FUN = ISOdatetime, Year, Month, Day, Hour, Minute, 60, "EST")) Where Year, Month etc are all numeric. I think ISOdatetime should return a POSIXct object. However, the result I obtained from the line above is all numeric. Could you please advise? I wish to get POSIXct. Thank you

The following three calls all produce the same result (my machine is in EST): > as.POSIXct(0, tz="", origin=ISOdatetime(1970,1,1,10,0,0)) [1] "1970-01-01 10:00:00 EST" > as.POSIXct(0, tz="EST", origin=ISOdatetime(1970,1,1,10,0,0)) [1] "1970-01-01 10:00:00 EST" > as.POSIXct(0, tz="GMT", origin=ISOdatetime(1970,1,1,10,0,0)) [1]

I'm having problems entering dates and times around when daylight savings time starts. If I type (on R 1.8.1 on Gentoo Linux) > ISOdatetime(2004,4,4,0:4,0,0,"GMT") [1] "2004-04-03 19:00:00 EST" "2004-04-03 20:00:00 EST" [3] "2004-04-03 22:00:00 EST" "2004-04-03 22:00:00 EST" [5] "2004-04-03 23:00:00 EST" Giving the times

Hello, I have been trying to plot correctly a graph for 2 month now, with no success.I want to put a grid, adjusted on the X axis tickers. Here is the way I build my X-Axis and my grid: grid(11, NULL, col="grey40") axis(2) # build the tickers on the beginning of each monthticks.at <- seq(ISOdatetime(lastYear, 01, 01, hour=0, min=0, sec=0, tz="GMT"),

Hi R users, I am using xlsReadWrite to read a particular excel file. In one of the columns I have dates ( say col=5). Now date column is read by default as numeric. So I used dateTimeAs= "isodatetime". This enables reading in the date format. However in the earlier column (say col=1) I have data which however starts from row 10. So to read data from column one I use

I create a zooreg object that runs from Jan-1-2002 0:00 to Jun-1-2005 0:00... regts.start = ISOdatetime(2002, 1, 1, hour=0, min=0, sec=0, tz="") regts.end = ISOdatetime(2005, 6, 1, hour=0, min=0, sec=0, tz="") regts.zoo <- zooreg( NA, regts.start, regts.end, deltat=3600 ) Upon inspection: > regts.zoo[1:3] 2002-01-01 00:00:00 2002-01-01 01:00:00 2002-01-01 02:00:00