[R] Compare output of Violin plot from ggplot2 and vioplot . Need Explanation

Mohammad Tanvir Ahamed mashranga at yahoo.com
Mon Jul 24 15:59:13 CEST 2017


Hi, 

I have made violin plot with both ggplot2 and vioplot package with same data. 
The results and code are as follows. 

###################  Loading data 
data.melt <- dget("https://gubox.box.com/shared/static/rirth0eym114afwyjxwe128sjzipzdym.txt")

###################  Violin plot by library(vioplot)
library(vioplot)
data.use_11<- data.melt$value[data.melt$ident == 0]
data.use_12<- data.melt$value[data.melt$ident == 1]
data.use_13<- data.melt$value[data.melt$ident == 2]
data.use_14<- data.melt$value[data.melt$ident == 3]
data.use_15<- data.melt$value[data.melt$ident == 4]
data.use_16<- data.melt$value[data.melt$ident == 5]
data.use_17<- data.melt$value[data.melt$ident == 6]
data.use_18<- data.melt$value[data.melt$ident == 7]
data.use_19<- data.melt$value[data.melt$ident == 8]
data.use_110<- data.melt$value[data.melt$ident == 9]
vioplot(data.use_11,data.use_12,data.use_13,data.use_14,data.use_15,
               data.use_16, data.use_17,data.use_18,data.use_19,data.use_110, h = 0.2, drawRect = FALSE)
## Violin plot 
https://i.stack.imgur.com/0taf3.jpg



##################### Violin plot by library(ggplot2)
library(ggplot2)
p  <- ggplot(data.melt,aes(factor(ident),value))
p2 <- p + geom_violin(scale="width",adjust=adjust.use,trim=TRUE,aes(fill=factor(ident)))
p2
## Violin plot 
https://i.stack.imgur.com/gg6Sh.jpg



##################### Questions
In those both figure, scale on x-axis (1 to 9 and 0 to 9) both are same . They are the same event.  
I was expecting the above 2 figures should be same (Same density presentation). But why the density representation of both picture are different ?
Can any one please explain ? 

I thought , scale parameter in geom_violin (ggplot2) plot could be a reason and  the explanation of scale parameter said in the package. But i am not clear what they are saying

scale : 
if "area" (default), all violins have the same area (before trimming the tails). If "count", areas are scaled proportionally to the number of observations. If "width", all violins have the same maximum width.

Can any one please explain what this scale parameter do and why two plot is different ?     Thanks !! 


Regards.............
Tanvir Ahamed 
Stockholm, Sweden     |  mashranga at yahoo.com 
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