[R] Odp: Correctly plotting bar and scatter chart on 2-y axis plot with par(new=T)

[Petr PIKAL]

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. 
> -- 
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> 
plotting-bar-and-scatter-chart-on-2-y-axis-plot-with-par-new-T-tp2266589p2266589.html
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