[GRASS-stats] sequence of dates by one hour

[Matteo Dall'Amico]

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Hello,

I need to create a sequence of dates separated by one hour.

I found in the examples of axis.POSIXct() that it is possible to create it:

Examples

with(beaver1, {

time <- strptime(paste(1990, day, time %/% 100, time %% 100),

                 "%Y %j %H %M")

plot(time, temp, type="l") # axis at 4-hour intervals.

# now label every hour on the time axis

plot(time, temp, type="l", xaxt="n")

r <- as.POSIXct(round(range(time), "hours"))

axis.POSIXct(1, at=seq(r[1], r[2], by="hour"), format="%H")

})

I tried, but I received the error:

date_graph_in<-chron("1/11/1907","00:39:00",format = c(dates = "d/m/y", times = "h:m:s"));

date_graph_fin<-chron("1/11/1998","00:39:00",format = c(dates = "d/m/y", times = "h:m:s"));

data_seq<-seq(date_graph_in,date_graph_fin,by="hour")

Error in seq.dates(date_graph_in, date_graph_fin, by = "hour") : 

"by" must be one of days, weeks, months, or years

It seems it is possible to create date sequences separated of days, weeks, months or years but not for hours.

Does someone know how to do it?

Thanks in advance,

Matteo

---------------------------------

Matteo Dall'Amico

PhD candidate

CUDAM and department of Civil and Environmental Engineering

Universita' degli Studi di Trento

Via Mesiano 77 - 38050 Trento - Italy

email: [hidden email]

Tel. [phone]

Fax [phone]

http://www.dottorato.it/trento/

---------------------------------

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[Roger Bivand]

On Tue, 15 Jan 2008, Matteo Dall'Amico wrote:

Matteo,

Could you please post this on R-help, if you need an answer from someone
who uses these classes?

Roger

> Hello,
> I need to create a sequence of dates separated by one hour.
> I found in the examples of axis.POSIXct() that it is possible to create it:
>
> Examples
>
> with(beaver1, {
> time <- strptime(paste(1990, day, time %/% 100, time %% 100),
>                "%Y %j %H %M")
> plot(time, temp, type="l") # axis at 4-hour intervals.
> # now label every hour on the time axis
> plot(time, temp, type="l", xaxt="n")
> r <- as.POSIXct(round(range(time), "hours"))
> axis.POSIXct(1, at=seq(r[1], r[2], by="hour"), format="%H")
> })
>
>
> I tried, but I received the error:
>
> date_graph_in<-chron("1/11/1907","00:39:00",format = c(dates = "d/m/y", times
> = "h:m:s"));
> date_graph_fin<-chron("1/11/1998","00:39:00",format = c(dates = "d/m/y",
> times = "h:m:s"));
> data_seq<-seq(date_graph_in,date_graph_fin,by="hour")
>
> Error in seq.dates(date_graph_in, date_graph_fin, by = "hour") :
> "by" must be one of days, weeks, months, or years
>
>
> It seems it is possible to create date sequences separated of days, weeks,
> months or years but not for hours.
>
> Does someone know how to do it?
> Thanks in advance,
>
> Matteo
>
> ---------------------------------
> Matteo Dall'Amico
> PhD candidate
> CUDAM and department of Civil and Environmental Engineering
> Universita' degli Studi di Trento
> Via Mesiano 77 - 38050 Trento - Italy
> email: [hidden email]
> Tel. [phone]
> Fax [phone]
> http://www.dottorato.it/trento/
> ---------------------------------
>
>
>

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: [phone]; fax [phone]
e-mail: [hidden email]

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