[R] plot centered line on barplot

[Uwe Ligges]

claudio.is at libero.it wrote:
> Dear R user,
> 
> I need plot an histogram for the occurrence of a dataset, and then add a line corresponding to the freuqnecy of another similar dataset. in order to do this i used the function 
>> hist_data1=hist(data1, breaks= seq(0,50,5), plot=FALSE)
>> hist_data2=hist(data2, breaks= seq(0,50,5), plot=FALSE)
> 
> then I plotted the frequency
> 
>> barplot(hist_data1$density)
>> lines(hist_data1$density)


barplot() returns the positions on x-axis (these may be non-integers) 
where it draws the plots, hence you can say:

  bp <- barplot(hist_data1$density)
  lines(bp, hist_data1$density)


> but the line is shifted in respect to the center of the bars. how can I properly plot the line? another question. this is easy, how can I smooth the curve (not fit with loess of spline)?

If you do not tell us which kind of smoother you prefer ....

Uwe Ligges



> 
> tnx
> 
> --
> Claudio
> ______________________________________________
> R-help at 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.