[R] Simple spectral analysis
Hello world, I am actually trying to transfer a lecture from Statistica to R and I ran into problems with spectral analysis, I think I just don't get it 8-( (The posting from FFT, frequs, magnitudes, phases from 2005 did not enlighten me) As a starter for the students I have a 10year data set of air temperature with daily values and I try to get a periodogram where the annual period (365 days) should be clearly visible (in statistica I can get the frequencies and the period). I tried the spectrum() and pgram() functions, but did not find a way through... The final aim would be to get the periodogram (and the residuals from the reassembled data set...) Thanks and greetings, Georg The data set: air = read.csv(http://www.hydrology.uni-kiel.de/~schorsch/air_temp.csv;) airtemp = ts(T_air, start=c(1989,1), freq = 365) plot(airtemp) -- Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany +49/431/23761412, mo: +49/171/4995884, icq:348340729, skype: ghoermann __ R-help@stat.math.ethz.ch mailing list 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.
Re: [R] Simple spectral analysis
Peter Dalgaard wrote: Earl F. Glynn wrote: The defaults for detrending and tapering could be involved. Putting, e.g., detrend=F gives me a spectrum with substantially higher low-frequency components. But what was the problem in the first place? understanding how this things work in R compared to other packages 8-) Thanks a lot for the help. I will post the script when its ready (an introduction for our biology students to time series, just 8 hours) Georg -- Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany +49/431/23761412, mo: +49/171/4995884, icq:348340729, skype: ghoermann __ R-help@stat.math.ethz.ch mailing list 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.
[R] Strange Colnames
Hello world,
I am trying to create a matrix of lagged time series with the
following code fragment (I know that I can use acf-function...).
I want to set the variable/column name to something like
lag 1 etc. If I try to do it I get text like
lagtest.lagtest.lagtest.lag 1 where does this come from?
After a conversion to a data.frame it works as expected.
What did I miss?
Thanks and greetings,
Georg
==
lagtest - as.ts(seq(1:100)) ;
for (i in 1:4) {lagtest - cbind(lagtest,lag(ts_test,i));
colnames(lagtest)[i+1]- paste(lag,i)}
colnames(lagtest)[1]-H_GW;
colnames(lagtest)
[1] H_GW lagtest.lagtest.lagtest.lag 1
lagtest.lagtest.lag 2
[4] lagtest.lag 3 lag 4
# this works...
t5 - as.data.frame(lagtest)
for (i in 1:4) {names(t5)[i+1] - paste(var,i) }
names(t5)
[1] H_GW var 1 var 2 var 3 var 4
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Re: [R] Strange Colnames
Miguel A. Arranz wrote: You probably want to have a look at help(embed). It might be all you need. embed wraps around (no NAs at begin and end of the dataset), this makes no sense in hydrology. Gruss Georg -- Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany Tel. 0431-880-1207, Home: 0451/477032, 0172/4315715, Penguin #189476 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Strange Colnames
Gabor Grothendieck wrote: Here is something you could try: # define lags and their names lags - 0:4 names(lags) - c(G_HW, paste(lag, 1:4)) # build mts do.call(cbind, lapply(lags, lag, x = lagtest)) thank you for the solution, I will try to understand it during the weekend 8-) Now I tried to change the lag from the default value of 1 to -1, but I apparently missed something: do.call(cbind, lapply(lags, function(x) lag(x,-1), x = lagtest)) Error in FUN(X[[1]], ...) : unused argument(s) ( ...) where is the unused argument? Thanks, Georg -- Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany Tel. 0431-880-1207, Home: 0451/477032, 0172/4315715, Penguin #189476 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
[R] Getting *types* of arguments?
Hello world, short question: is there a possibility to get a list of arguments of a function *with* variable/parameter types? formals() gives me the names of the parameters, but says nothing about the parameter type it expects (I know I can always use the help function). I would like somthing like $x: vector or data.frame... Thanks in advance... Georg -- Georg Hoermann, Fachabteilung Wasserwirtschaft / Dep. Hydrology Ecosystem Research Center, Kiel University, Germany, Penguin #189476 Tel. 0431-880-1207, 0172/4315715, ICQ: 348340729, MSN: hlschorsch __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
[R] Annual cumulative sums from time series
Hello world, I am actually transferring a course in data management for students in biology, geography and agriculture from statistica to R - it works surprisingly well. If anyone is interested in my scratch/notepad (in German language), please see www.hydrology.uni-kiel.de/~schorsch/statistik/statistik_datenauswertung.pdf (pages 40-52) The dataset is: www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv It contains a 10 year dataset. So far for introduction, now comes the problem: we often need cumulative *annual* sums (sunshine, precipitation), i.e. the sum must reset to 0 at the beginning of the year. I know of cumsum(), but I do not now how to split the dataset automagically into annual pieces so I can cumsum() every year separately. I have the strong hope that the solution is one of these one-liners which leave the students with eyes wide open in surprise and makes them true believers in the power of the command-line 8-). Thanks Greetings Georg -- Georg Hoermann, Luebeck, Germany Tel. 0451/47 70 32, 0172/431 57 15, Penguin #189476 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Annual cumulative sums from time series - SOLVED + questions
Roger Bivand wrote: On Thu, 10 Feb 2005, Georg Hoermann wrote: Hello world, based on the code of Roger I have now two solutions: the first one (one line for the whole dataset) - cut here -- erle - read.csv(url(http://www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv;)) jahre - factor(substring(erle$DATUM, 7)) tpks1 - unlist(tapply(erle$Sonnen, jahre, cumsum)) plot(tpks1, type=l) - cut here --- The second one plots one line for each year: start - cut here # read data in from Internet erle - read.csv(url(http://www.hydrology.uni-kiel.de/~schorsch/statistik/erle_stat.csv;)) # extract Year as a factor from variable DATUM jahre - factor(substring(erle$DATUM, 7)) try1 - tapply(erle$Sonnen, jahre, cumsum) # create colors for every year from rainbow color scheme cols - rainbow(length(try1)) plot(x=c(1,366), y=c(0,1200), type=n, xlab=Days, ylab=Cumulative sunshine (h)) # draw the lines, one line for each year for (i in 1:length(try1)) lines(1:length(try1[[i]]), try1[[i]], col=cols[i]) # ...and the legend legend(c(0,100), c(400,1100), names(try1), col=cols, lwd=1, bty=n) end cut here - For the second example, a mean sum for all years would also be a good idea... Thanks for all solutions... Merci Gruss Georg -- Georg Hoermann, Dep. of Hydrology, Ecology, Kiel University, Germany Tel. 0431-880-1207, icq - 348 340 729, 0172/4315715, Penguin #189476 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
