R help - Jul 2007 - plot centered line on barplot

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)
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)?


tnx

--
Claudio

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
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