R help - Feb 2013 - help on plotting series with different x-axis values on a graph with one x-axis

Hi,
I have run into this problem a couple of times now and hope you can help!

If I want to plot  mulitiple series with differing x-axis values (however, all
in the same range) in 1 plot with one common axis R obstruses the plots.

E.g. if I plot water content against time and I start with the sampler at 5 cm
depth, it plots that one right.
But the next depth, 15 cm, is measured at slightly different time intervals  and
so R will not plot the series correctly.
Reading in the data using  ? stringsAsFactors=FALSE? helps, but the lines are
still plottet in an akward fashion (edgy) , see attached image.
Hope you can help!
eike



Eike Marie Thaysen

Ph.d. studerende

ECO

Institut for Kemiteknik DTU

Danmarks Tekniske Universitet

[dtu]

Ris? Campus

Frederiksborgvej 399

Bygning 309

4000  Roskilde
Telefon: 51801481



emth at kt.dtu.dk<mailto:emth at risoe.dtu.dk>

www.dtu.dk<http://www.risoe.dtu.dk/>

On Feb 9, 2013, at 4:52 AM, Eike Marie Thaysen wrote:
>
> Hi,
> I have run into this problem a couple of times now and hope you can  
> help!
>
> If I want to plot  mulitiple series with differing x-axis values  
> (however, all in the same range) in 1 plot with one common axis R  
> obstruses the plots.
>
> E.g. if I plot water content against time and I start with the  
> sampler at 5 cm depth, it plots that one right.
> But the next depth, 15 cm, is measured at slightly different time  
> intervals  and so R will not plot the series correctly.
> Reading in the data using  ? stringsAsFactors=FALSE? helps, but the  
> lines are still plottet in an akward fashion (edgy) , see attached  
> image.
> Hope you can help!
> eike
No image was attached. It was probably in a format the the mail server  
would not accept. PDF files are the only one listed as being  
acceptable, but I think from experience that PNG files might also make  
it through. It would probably also help if you offered the output of  
str(dfrm) on whateever dataframe you are working with.


-- 
David.
>
>
>
> Eike Marie Thaysen
>
> Ph.d. studerende
>
> ECO
>
> Institut for Kemiteknik DTU
>
> Danmarks Tekniske Universitet
>
> [dtu]
>
> Ris? Campus
>
> Frederiksborgvej 399
>
> Bygning 309
>
> 4000  Roskilde
> Telefon: 51801481
>
>
>
> emth at kt.dtu.dk<mailto:emth at risoe.dtu.dk>
>
> www.dtu.dk<http://www.risoe.dtu.dk/>
>
>
> ______________________________________________
> 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.
David Winsemius, MD
Alameda, CA, USA

No image. png files seem to make it through so if you save as png it should
arrive.

Some sample code and data would help

Is the data in one data.frame or could you put it into one?  If so you might
want to try melting the data (see reshape 2 package) and plotting with ggplot2

John Kane
Kingston ON Canada

> -----Original Message-----
> From: emth at kt.dtu.dk
> Sent: Sat, 9 Feb 2013 12:52:32 +0000
> To: r-help at r-project.org
> Subject: [R] help on plotting series with different x-axis values on a
> graph with one x-axis
> 
> 
> Hi,
> I have run into this problem a couple of times now and hope you can help!
> 
> If I want to plot  mulitiple series with differing x-axis values
> (however, all in the same range) in 1 plot with one common axis R
> obstruses the plots.
> 
> E.g. if I plot water content against time and I start with the sampler at
> 5 cm depth, it plots that one right.
> But the next depth, 15 cm, is measured at slightly different time
> intervals  and so R will not plot the series correctly.
> Reading in the data using  ? stringsAsFactors=FALSE? helps, but the lines
> are still plottet in an akward fashion (edgy) , see attached image.
> Hope you can help!
> eike
> 
> 
> 
> Eike Marie Thaysen
> 
> Ph.d. studerende
> 
> ECO
> 
> Institut for Kemiteknik DTU
> 
> Danmarks Tekniske Universitet
> 
> [dtu]
> 
> Ris? Campus
> 
> Frederiksborgvej 399
> 
> Bygning 309
> 
> 4000  Roskilde
> Telefon: 51801481
> 
> 
> 
> emth at kt.dtu.dk<mailto:emth at risoe.dtu.dk>
> 
> www.dtu.dk<http://www.risoe.dtu.dk/>
> 
> 
> ______________________________________________
> 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.
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On 02/09/2013 11:52 PM, Eike Marie Thaysen wrote:
>
> Hi,
> I have run into this problem a couple of times now and hope you can help!
>
> If I want to plot  mulitiple series with differing x-axis values (however,
all in the same range) in 1 plot with one common axis R obstruses the plots.
>
> E.g. if I plot water content against time and I start with the sampler at 5
cm depth, it plots that one right.
> But the next depth, 15 cm, is measured at slightly different time intervals
and so R will not plot the series correctly.
> Reading in the data using  ? stringsAsFactors=FALSE? helps, but the lines
are still plottet in an akward fashion (edgy) , see attached image.
> Hope you can help!
Hi eike,
I'll do a bit of guessing to see if it helps. First, I think that your 
times are being read in as factors (they are probably formatted like "11 
Feb 2013 13:23:37" or similar and read as character strings). As you are 
probably sampling at fairly equal intervals, the fact that the factors 
are represented by integers starting with 1 may look okay. What you may 
want is to convert these to date/time objects (say the data frame is 
"mydata" and the times are "sample_time"):

mydata$sample_time<-strptime(mydata$sample_time,
  format="%d %b %Y %H:%M:%S")

or something like that. Then the x axis will be in units of date/time 
and your second series will be plotted correctly. By calling the lines 
"edgy" perhaps you mean that they are not smooth curves. You may want
to
use the "approx" function or a smoothing function to smooth out the 
lines and plot those curves instead.

Having the data would help, so if you could "dput" your data or a
small
subset of it, we could give better suggestions.

Jim