Re: [R] using its to import time series data with uneven dates

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Wed 13 Jul 2005 - 09:02:14 EST

On 7/12/05, Sheri Conner Gausepohl <sheri@atmos.colostate.edu> wrote:
> Good day:
>
> I am trying to use
> readcsvIts("nwr_data_qc.txt",informat=its.format("%Y%m%d%h%M
> %Y"),header=TRUE,sep="",skip=0,row.names=NULL,as.is=TRUE,dec=".")
>
> to read in a file (nwr_data_qc.txt) that looks like this:
>
> Time Y M D H Min CO2
> 2000.18790 2000. 3. 9. 18. 30. 373.60
> 2000.20156 2000. 3. 14. 18. 30. 373.34
> 2000.22609 2000. 3. 23. 18. 0. 373.01
>
> and R returns this:
>
> Y M D H Min CO2
> <NA> 2000 3 9 18 30 373.60
> <NA> 2000 3 14 18 30 373.34
> <NA> 2000 3 23 18 0 373.01
>
> I have tried every format option on the help page. How can I read in
> my decimal dates (e.g., 2000.18790)?
>
> Note that these data (CO2) are irregularly spaced in time (Time).
>
> Ultimately I would like to fit a trigonometric polynomial (first
> harmonic) to these data in order to smooth them and obtain values
> between measurements. Any suggestions you can provide on how to do
> this would be much appreciated.
>
> Thank you for your help.
>
> Sheri
>
> Sheri L. Conner Gausepohl
> Graduate Research Assistant
> Department of Atmospheric Science
> Colorado State University

Try this:

library(its)
dd <- read.table(myfile, header = TRUE)
tt <- paste(dd$Y, "-", dd$M, "-", dd$D, " ", dd$H, ":", dd$Min, sep = "") co2 <- its(dd$CO2, as.POSIXct(tt))
co2 # display co2



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