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

[Whit Armstrong]

You would probably do better to read in your data and reformat the
dates.

What date format is 2000.18790?  The Its package uses POSIXct dates and
readcsvIts expects the formats to be "%Y-%m-%d" unless you've changed
the default format.



-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Sheri Conner
Gausepohl
Sent: Tuesday, July 12, 2005 5:47 PM
To: r-help at stat.math.ethz.ch
Subject: [R] using its to import time series data with uneven dates

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

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