[R] timeseries

[Joris Meys]

Difficult to guess why, but I reckon you should use ts() instead of
as.ts. Otherwise set the tsp-attribute correctly. Eg :

> x <- cumsum(1+round(rnorm(20),2))
> as.ts(x)
Time Series:
Start = 1
End = 20
Frequency = 1
 [1]  0.87  3.51  4.08  4.20  3.25  4.63  6.30  6.89  9.28  9.93 10.19
 9.97 10.20 11.51 11.52 11.53 12.97 14.04 17.02 18.47

> tseries <- ts(x,frequency=12,start=c(2004,3))
> tseries
       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
2004              0.87  3.51  4.08  4.20  3.25  4.63  6.30  6.89  9.28  9.93
2005 10.19  9.97 10.20 11.51 11.52 11.53 12.97 14.04 17.02 18.47

> tsp(x) <- c(2004+2/12,2005.75,12)
> as.ts(x)
       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
2004              0.87  3.51  4.08  4.20  3.25  4.63  6.30  6.89  9.28  9.93
2005 10.19  9.97 10.20 11.51 11.52 11.53 12.97 14.04 17.02 18.47

See ?ts to get the options right. I suggest to use the function ts()
instead of assigning the tsp attribute.
)
Cheers
Joris


On Mon, Jul 5, 2010 at 9:35 AM, nuncio m <nuncio.m at gmail.com> wrote:
> Dear useRs,
> I am trying to construct a time series using as.ts function, surprisingly
> when I plot
> the data the x axis do not show the time in years, however if I use
> ts(data), time in years are shown in the
> x axis.  Why such difference in the results of both the commands
> Thanks
> nuncio
>
>
> --
> Nuncio.M
> Research Scientist
> National Center for Antarctic and Ocean research
> Head land Sada
> Vasco da Gamma
> Goa-403804
>
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-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
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