I am working with time-date data to plot temporal activity. I would like to create a "template" to repeat the date and time for all potential data sets that may have differing time zone origins. Reading the > ?strptime help section I note that time zone is a variable to add. Looking at the output of a sample data set Species Location Date Time 1 Sppaaa One 1/13/2009 17:00 2 Sppaaa One 1/13/2009 18:00 3 Sppaaa One 1/13/2009 19:00 4 Sppaaa One 1/13/2009 20:00 5 Sppaaa One 1/13/2009 21:00... in order to understand how R is handling this and using: > All$Time <- as.POSIXct(strptime(as.character(d$Time), "%H:%M")) > All$Time [1] "2009-03-14 17:00:00 CST" "2009-03-14 18:00:00 CST" [3] "2009-03-14 19:00:00 CST" "2009-03-14 20:00:00 CST" [5] "2009-03-14 21:00:00 CST" "2009-03-14 22:00:00 CST" It appears that the default is using CST and this is I assume based on my system setting for my PC time. Is there a way to NOT have it do this as the data I am processing are from a different time zone. Tnx Bruce
I am working with time-date data to plot temporal activity. I would like to create a "template" to repeat the date and time for all potential data sets that may have differing time zone origins. Reading the > ?strptime help section I note that time zone is a variable to add. Looking at the output of a sample data set Species Location Date Time 1 Sppaaa One 1/13/2009 17:00 2 Sppaaa One 1/13/2009 18:00 3 Sppaaa One 1/13/2009 19:00 4 Sppaaa One 1/13/2009 20:00 5 Sppaaa One 1/13/2009 21:00... in order to understand how R is handling this and using: > All$Time <- as.POSIXct(strptime(as.character(d$Time), "%H:%M")) > All$Time [1] "2009-03-14 17:00:00 CST" "2009-03-14 18:00:00 CST" [3] "2009-03-14 19:00:00 CST" "2009-03-14 20:00:00 CST" [5] "2009-03-14 21:00:00 CST" "2009-03-14 22:00:00 CST" It appears that the default is using CST and this is I assume based on my system setting for my PC time. Is there a way to NOT have it do this as the data I am processing are from a different time zone. Tnx Bruce
Read this from the as.POSIXct help page more carefully: "Usage as.POSIXct(x, tz = "", ...)" "tz A timezone specification to be used for the conversion, if one is required. System-specific (see time zones), but "" is the current timezone, and "GMT" is UTC (Universal Time, Coordinated)." -- David Winsemius On Mar 14, 2009, at 9:52 AM, Neotropical bat risk assessments wrote:> I am working with time-date data to plot temporal activity. > > I would like to create a "template" to repeat the date and time for > all potential data sets that may have differing time zone origins. > > Reading the > ?strptime help section I note that time zone is a > variable to add. > Looking at the output of a sample data set > Species Location Date Time > 1 Sppaaa One 1/13/2009 17:00 > 2 Sppaaa One 1/13/2009 18:00 > 3 Sppaaa One 1/13/2009 19:00 > 4 Sppaaa One 1/13/2009 20:00 > 5 Sppaaa One 1/13/2009 21:00... > > in order to understand how R is handling this and using: > > > All$Time <- as.POSIXct(strptime(as.character(d$Time), "%H:%M")) > > All$Time > [1] "2009-03-14 17:00:00 CST" "2009-03-14 18:00:00 CST" > [3] "2009-03-14 19:00:00 CST" "2009-03-14 20:00:00 CST" > [5] "2009-03-14 21:00:00 CST" "2009-03-14 22:00:00 CST" > > It appears that the default is using CST and this is I assume based > on my system setting for my PC time. > Is there a way to NOT have it do this as the data I am processing > are from a different time zone. > > Tnx > > BruceDavid Winsemius, MD Heritage Laboratories West Hartford, CT