[R] Odp: FW: RES: bug in axis.Date? was (Re: newbie needs help plottingtimeseries)

From: Petr PIKAL <petr.pikal_at_precheza.cz>
Date: Wed, 02 Jul 2008 15:15:27 +0200

Hi

Is it from chron package? As I do not have it available now I can not try it but the problem is not in plotting itself but in custom x axis labeling when there are missing date on either end of a series.

You have several options

Define fake time values for yet nonexisting data. Do your labeling only for existing values. Use xlim when calling your plot (which seems to me the most suitable)

compare

x<-1:10
y<-1:10
x[8:10]<-NA
y[8:10]<-NA
plot(x, y, axes=F)
box()
axis(1, at=1:10, labels=11:20)

with this

x<-seq(as.Date("2004-01-01"), as.Date("2008-06-01"),by="month") x[50:54] <-NA
y <- seq(405,410,length=54)
y[50:54] <-NA
plot(x, y, axes=FALSE, ylim=c(405,410),col="red", pch=15, type="o", ylab="metres above sea level", main="Main Plot Title") axis(2, at=405:410, tck=1, col="gray60")

axis.Date(1, at=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
by="month"), labels=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
by="month"), tck=1, col="gray60")

which shall basically do the same. When you set explicit limits in plotting you can get rid of subsequent error in labeling axis.

plot(x, y, axes=FALSE, ylim=c(405,410),col="red", pch=15, type="o", ylab="metres above sea level", main="Main Plot Title", xlim=c(as.Date("2004-01-01"), as.Date("2008-06-01")))

OK, It is not bug, but you has to go quite deep into axis.Date function to undestand what is going on and how to avoid such behaviour.

Regards
Petr

r-help-bounces_at_r-project.org napsal dne 02.07.2008 14:29:24:

>
> Instead of
> x<-seq(as.Date("2004-01-01"), as.Date("2008-06-01"),by="month")
>
> from=iso2chron("2004-01-01")
> to= iso2chron("2008-06-01")
>
> from <-chron2UTCsecs(from)
> to<-chron2UTCsecs(to)
>
> delta##how many secs i.e month time in secs
>
> xx <- seq(from=from, to=to, by=delta)
> x <- UTCsecs2chron(xx)
>
> I think it will works
>
>
>
>
> -----Original Message-----
> From: r-help-bounces_at_r-project.org [mailto:r-help-bounces_at_r-project.org]
> On Behalf Of Leandro Marino
> Sent: Wednesday, July 02, 2008 5:47 PM
> To: Petr PIKAL; Kathi
> Cc: r-help_at_stat.math.ethz.ch
> Subject: [R] RES: bug in axis.Date? was (Re: newbie needs help
> plottingtimeseries)
>
> You can do this plot saying to R that your file is a time series with
> the
> ts() function.
>
>
> serie=ts(x,....)
> and then you use plot(serie)
>
> -----Mensagem original-----
> De: r-help-bounces_at_r-project.org [mailto:r-help-bounces_at_r-project.org]Em
> nome de Petr PIKAL
> Enviada em: quarta-feira, 2 de julho de 2008 05:04
> Para: Kathi
> Cc: r-help_at_stat.math.ethz.ch
> Assunto: [R] bug in axis.Date? was (Re: newbie needs help plotting
> timeseries)
>
>
> Hi
>
> "Kathi" <kathi_at_dropnet.ch> napsal dne 01.07.2008 18:48:47:
>
> > On Tue, 1 Jul 2008 14:33:12 +0200, Petr PIKAL wrote
> > > "Kathi" <kathi_at_dropnet.ch> napsal dne 01.07.2008 13:39:18:
> > >
> > > > Thanks, Petr.
> > > >
> > > > After fiddling around some more with my code I found out that this
> seems
> > > to
> > > > have something to do
> > > > with the number of records the table I'm reading (here: column
> B112).
> > > Somehow,
> > > > changing the
> > > > number of records for B112 changes the numbers in the error
> message
> -
> > > though I
> > > > don't quite
> > > > understand how the number of records influences the axis intervals
> or
> > > their
> > > > labels, since I define
> > > > those explicitly...
> > >
> > > Neither I. So I sent it to r-help maybe somebody else will know. If
> > > you debug code of axis.Date you find that after some computing there
> > > is this comparison where range is based on your input data (in your
> > > case x), and z is from defined at sequence of dates.
> > >
> > > z <- z[z >= range[1] & z <= range[2]]
> > >
> > > and this comparison results in character(0), when plotting with this
> > > artificial example.
> > >
> > > plot(1:100, seq(405,410,length=100), axes=FALSE, ylim=c(405,410),
> > > col="red", pch=15,
> > > type="o", ylab="metres above sea level", main="Main Plot Title")
> > > axis(2, at=405:410, tck=1, col="gray60")
> > > axis.Date(1, at=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
> > > by="month"), labels=seq(as.Date("2004-01-01"),
> as.Date("2008-06-01"),
> > > by="month"), tck=1, col="gray60")
> > >
> > > I presume, that your x is from different interval of dates or it is
> > > not a date.
> >
> > My data comes from a groundwater monitoring program. Once a month the
> water surface is
> > measured in some 170 stations, and I've been using R to visualize
> these
> > measurements. In this
> > particular case, the water table ranges between approximately 406 and
> 408
> > metres above sea level,
> > hence the y axis interval between 405 and 410.
> > The values of my column x are dates of the format YYYY-MM-DD. If
> something
> > were wrong there,
> > then I guess I would not be able to plot my data at all. But using the
> limits
> > of 2004-01-01 and
> > 2008-06-01, I can plot all the timelines for my 170 measuring stations
> without
> > any problem. But
> > since it's now July, I wanted to shift the view by half a year. So I
> used
> > "search and replace" in my code
> > to change to 2004-07-01 and 2008-12-01 (plus six months in both
> cases).
> That's
> > when I got the
> > error. I almost have a feeling that R doesn't like the "empty" part of
> the
> > graph for July-December... I
> > don't understand why this happens, but maybe it has something to do
> with
> the
> > comparison of ranges
> > you mentioned.
>
> OK, It seems that you are right. Maybe you could add some expected x
> date/time values so that x axis will have no NA values.
>
> x<-seq(as.Date("2004-01-01"), as.Date("2008-06-01"),by="month")
> y <- seq(405,410,length=54)
> y[50:54] <-NA
> plot(x, y, axes=FALSE, ylim=c(405,410),col="red", pch=15,
> type="o", ylab="metres above sea level", main="Main Plot Title")
> axis(2, at=405:410, tck=1, col="gray60")
> axis.Date(1, at=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
> by="month"), labels=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
> by="month"), tck=1, col="gray60")
>
> as you see, then everything works. However I think that it is pretty
> close
> to bug in axis.Date, maybe somebody can enlighten us both :-)
>
> Regards
> Petr
>
>
> >
> > Thanks for all your help!
> >
> > Kathi
> >
> > >
> > > Regards
> > > Petr
> > >
> > > >
> > > > Kathi
> > > >
> > > >
> > > > On Mon, 30 Jun 2008 11:48:43 +0200, Petr PIKAL wrote
> > > > > Hi
> > > > >
> > > > > r-help-bounces_at_r-project.org napsal dne 30.06.2008 11:14:48:
> > > > >
> > > > > > Dear R help list
> > > > > >
> > > > > > I have recently started using R to visualize time series of
> water
> > > level
> > > > > > measurements. The code I wrote
> > > > > > does exactly what I want:
> > > > > >
> > > > > > plot(x, a$B112, axes=FALSE, ylim=c(405,410), col="red",
> pch=15,
> > > > > > type="o", ylab="metres above sea level", main="Main Plot
> Title")
> > > > > > axis(2, at=405:410, tck=1, col="gray60")
> > > > > > axis.Date(1, at=seq(as.Date("2004-01-01"),
> as.Date("2008-06-01"),
> > > > > > by="month"), labels=seq(as.Date("2004-01-01"),
> > > as.Date("2008-06-01"),
> > > > > > by="month"), tck=1, col="gray60")
> > > > > >
> > > > > > Now I wanted to shift the data visualized by 6 months, so I
> replaced
> > >
> > > > > > "2004-01-01" by "2004-07-01"
> > > > > > and "2008-06-01" by "2008-12-01". Instead of the desired plot,
> I
> get
> > > an
> > > > > error
> > > > > > message stating
> > > > > > (forgive the perhaps faulty translation into English, I'm
> working on
> > > a
> > > > > German
> > > > > > version of R):
> > > > > >
> > > > > > mistake in axis(side, at = z, labels = labels, ...) :
> > > > > > length of 'at' and 'labels' different, 50 != 54
> > > > >
> > > > > Those two calls have different length
> > > > >
> > > > > at=seq(as.Date("2004-01-01"), as.Date("2008-06-01"), by="month")
> > > > > labels=seq(as.Date("2004-01-01"), as.Date("2008-06-01"),
> by="month")
> > > > >
> > > > > you can try it by
> > > > >
> > > > > length(seq(...))
> > > > >
> > > > > could not there be some typo in your call?
> > > > >
> > > > > Regards
> > > > >
> > > > > Petr
> > > > >
> > > > > >
> > > > > > What have I done wrong? Thank you very much for your help!
> > > > > >
> > > > > > Katharina Dubach
> > > > > >
> > > > > > ______________________________________________
> > > > > > R-help_at_r-project.org 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.
> > > >
> > > >
> > > > --
> > > > DropNet AG - Das Unternehmen fuer Ihren Internet-Auftritt!
> > > >
> > > >
> >
> >
> > --
> > DropNet AG - Das Unternehmen fuer Ihren Internet-Auftritt!
> >
> >
>
> ______________________________________________
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> ______________________________________________
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>
> ______________________________________________
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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. Received on Wed 02 Jul 2008 - 13:29:00 GMT

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