Dear list users,
I have wind data with frequency of 10 minutes (three years data). For
simplicity let me use only max wind speed.
I need to reduce the frequency to 30 minutes, at 00 (taking the mean of data
at 40, 50 and 00 minutes) and at 30 (taking the mean of data at 10, 20 and 30
minutes) of each hour.
The simple code here reported works well, but the column "interval" groups data
forward, not backward:
init_day <- as.POSIXct("2018-02-01-00-00", format="%Y-%m-%d-%H-%M",
tz="Etc/GMT-1")
fin_day <- as.POSIXct("2018-02-01-02-00", format="%Y-%m-%d-%H-%M",
tz="Etc/GMT-1")
mydf <- data.frame(data_POSIX=seq(init_day, fin_day, by="10 mins"))
mydf$vmax <- round(rnorm(13, 35, 10))
mydf$interval <- cut(mydf$data_POSIX, , breaks="30 min")
means <- aggregate(vmax ~ interval, mydf, mean)
data_POSIX vmax interval
1 2018-02-01 00:00:00 27 2018-02-01 00:00:00
2 2018-02-01 00:10:00 41 2018-02-01 00:00:00
3 2018-02-01 00:20:00 46 2018-02-01 00:00:00
4 2018-02-01 00:30:00 39 2018-02-01 00:30:00
5 2018-02-01 00:40:00 34 2018-02-01 00:30:00
6 2018-02-01 00:50:00 32 2018-02-01 00:30:00
...
I should work with
data_POSIX vmax interval
1 2018-02-01 00:00:00 27 2018-02-01 00:00:00
2 2018-02-01 00:10:00 41 2018-02-01 00:30:00
3 2018-02-01 00:20:00 46 2018-02-01 00:30:00
4 2018-02-01 00:30:00 39 2018-02-01 00:30:00
5 2018-02-01 00:40:00 34 2018-02-01 00:00:00
6 2018-02-01 00:50:00 32 2018-02-01 00:00:00
...
Is there a way to modify this code to groupp data correctly? (I would prefer
using only the base package)
Thank you for your help
Stefano
(oo)
--oOO--( )--OOo----------------
Stefano Sofia PhD
Civil Protection - Marche Region
Meteo Section
Snow Section
Via del Colle Ameno 5
60126 Torrette di Ancona, Ancona
Uff: 071 806 7743
E-mail: stefano.so...@regione.marche.it
---Oo---------oO----------------
________________________________
AVVISO IMPORTANTE: Questo messaggio di posta elettronica può contenere
informazioni confidenziali, pertanto è destinato solo a persone autorizzate
alla ricezione. I messaggi di posta elettronica per i client di Regione Marche
possono contenere informazioni confidenziali e con privilegi legali. Se non si
è il destinatario specificato, non leggere, copiare, inoltrare o archiviare
questo messaggio. Se si è ricevuto questo messaggio per errore, inoltrarlo al
mittente ed eliminarlo completamente dal sistema del proprio computer. Ai sensi
dell’art. 6 della DGR n. 1394/2008 si segnala che, in caso di necessità ed
urgenza, la risposta al presente messaggio di posta elettronica può essere
visionata da persone estranee al destinatario.
IMPORTANT NOTICE: This e-mail message is intended to be received only by
persons entitled to receive the confidential information it may contain. E-mail
messages to clients of Regione Marche may contain information that is
confidential and legally privileged. Please do not read, copy, forward, or
store this message unless you are an intended recipient of it. If you have
received this message in error, please forward it to the sender and delete it
completely from your computer system.
--
Questo messaggio stato analizzato da Libra ESVA ed risultato non infetto.
This message was scanned by Libra ESVA and is believed to be clean.
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
