R help - Jun 2010 - Correctly plotting bar and scatter chart on 2-y axis plot with par(new=T)

Hello Nabble users, 

A question about having two y axes on a chart. I'm trying to show on the
left (first) y axis a measure used in an experiment; the x axis shows the
experiment number, that has been sorted in a specific manner -- i.e. not
Experiments 1,2,3,n, but could be Experiment 6,1,18,n; the right (second) y
axis shows an experimental variable. The idea of the chart is to show how
results of the different experiments compare with one of the key variables
set in the experiment. 

The bar chart uses sorted data for its x axis, which have been determined by
experimental settings. So instead of the values on the x axis increasing
1,2,3,n, they instead refer to "Experiment 2", "Experiment
17", "Experiment
1", and so on. 

However, when I come to plot the second y axis, the scatter plot does not
work as anticipated. Instead of plotting the second axis data against
"Experiment 2", "Experiment 17", the data is plotted in
order -- i.e. 1,2,n.

The R procedure I'm using is:

1/ plot the bar chart
2/ use par(new=T) to allow me to produce the second y axis
3/ plot the scatter chart, on said second axis

Now, I'm assuming that this is due to my use of the par(new=T) function,
which I must admit I found on the internet, and am not completely sure what
it does. From what I can tell, however, it resets the plot area, so that
when I go to plot my scatter chart, the x axis set up in step 1/ is reset. 

As such, does anyone have any suggestions on how to make this work? 

Thanks in asvance. 
-- 
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Sent from the R help mailing list archive at Nabble.com.

Hi

r-help-bounces at r-project.org napsal dne 24.06.2010 09:44:49:
> 
> Hello Nabble users, 
> 
> A question about having two y axes on a chart. I'm trying to show on
the
> left (first) y axis a measure used in an experiment; the x axis shows 
the
> experiment number, that has been sorted in a specific manner -- i.e. not
> Experiments 1,2,3,n, but could be Experiment 6,1,18,n; the right 
(second) y
> axis shows an experimental variable. The idea of the chart is to show 
how
> results of the different experiments compare with one of the key 
variables
> set in the experiment. 
> 
> The bar chart uses sorted data for its x axis, which have been 
determined by
> experimental settings. So instead of the values on the x axis increasing
> 1,2,3,n, they instead refer to "Experiment 2", "Experiment
17",
"Experiment
> 1", and so on. 
> 
> However, when I come to plot the second y axis, the scatter plot does 
not
> work as anticipated. Instead of plotting the second axis data against
> "Experiment 2", "Experiment 17", the data is plotted in
order -- i.e.
1,2,n.
> 
> The R procedure I'm using is:
> 
> 1/ plot the bar chart
> 2/ use par(new=T) to allow me to produce the second y axis
> 3/ plot the scatter chart, on said second axis
> 
> Now, I'm assuming that this is due to my use of the par(new=T)
function,
> which I must admit I found on the internet, and am not completely sure 
what
> it does. From what I can tell, however, it resets the plot area, so that
> when I go to plot my scatter chart, the x axis set up in step 1/ is 
reset. 

Yes. You need to reset x values in desired order. But the exact code 
depends on what date you are plotting, how they are organised and what 
shall be desired order.

Or you can use of values which are returned by barplot and use them in 
further line adding after rescaling to fit y axis, something like

bbb<-barplot(VADeaths, beside = TRUE)
lines(bbb[,1], rnorm(5)+20)

Regards
Petr

> 
> As such, does anyone have any suggestions on how to make this work? 
> 
> Thanks in asvance. 
> -- 
> View this message in context: http://r.789695.n4.nabble.com/Correctly-
> 
plotting-bar-and-scatter-chart-on-2-y-axis-plot-with-par-new-T-tp2266589p2266589.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.

Using par(new=T) is dangerous and tricky for those people who understand what it
does and how to use it.  Trying to use it without fully understanding it will be
much worse.

I would use the updateusr function from the TeachingDemos package instead.  The
first example on the help page may give you the answer that you need (but it is
hard to tell from your description without code).  If that is not enough, send
the actual reproducible code (either include the data in a copy/pasteable way,
or use builtin or simulated data) that you tried and explain how it differs from
what you want the output to look like, then we will have a chance of being able
to help.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of dan.weavesham
> Sent: Thursday, June 24, 2010 1:45 AM
> To: r-help at r-project.org
> Subject: [R] Correctly plotting bar and scatter chart on 2-y axis plot
> with par(new=T)
> 
> 
> Hello Nabble users,
> 
> A question about having two y axes on a chart. I'm trying to show on
> the
> left (first) y axis a measure used in an experiment; the x axis shows
> the
> experiment number, that has been sorted in a specific manner -- i.e.
> not
> Experiments 1,2,3,n, but could be Experiment 6,1,18,n; the right
> (second) y
> axis shows an experimental variable. The idea of the chart is to show
> how
> results of the different experiments compare with one of the key
> variables
> set in the experiment.
> 
> The bar chart uses sorted data for its x axis, which have been
> determined by
> experimental settings. So instead of the values on the x axis
> increasing
> 1,2,3,n, they instead refer to "Experiment 2", "Experiment
17",
> "Experiment
> 1", and so on.
> 
> However, when I come to plot the second y axis, the scatter plot does
> not
> work as anticipated. Instead of plotting the second axis data against
> "Experiment 2", "Experiment 17", the data is plotted in
order -- i.e.
> 1,2,n.
> 
> The R procedure I'm using is:
> 
> 1/ plot the bar chart
> 2/ use par(new=T) to allow me to produce the second y axis
> 3/ plot the scatter chart, on said second axis
> 
> Now, I'm assuming that this is due to my use of the par(new=T)
> function,
> which I must admit I found on the internet, and am not completely sure
> what
> it does. From what I can tell, however, it resets the plot area, so
> that
> when I go to plot my scatter chart, the x axis set up in step 1/ is
> reset.
> 
> As such, does anyone have any suggestions on how to make this work?
> 
> Thanks in asvance.
> --
> View this message in context: http://r.789695.n4.nabble.com/Correctly-
> plotting-bar-and-scatter-chart-on-2-y-axis-plot-with-par-new-T-
> tp2266589p2266589.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.