Question

I am plotting boxplots from this data:

MY_LABEL     MY_REAL     MY_CATEGORY
1 [POS]       .56            POS
1 [POS]       .57            POS
1 [POS]       .37            POS
2 [POS]       .51            POS
1 [sim v]     .65            sim v
...

I’m using ggplot2:

ggplot( data=myDF, aes( x=MY_LABEL, y=MY_REAL, fill=MY_CATEGORY ) ) +
    scale_colour_manual( values=palette ) +
    coord_flip() + 
    geom_boxplot( outlier.size = 0 )

This works fine, and groups the boxplots by the field MY_CATEGORY:

I’d like to do 2 things:

1) To improve the clarity of this plot, I’d like to add separators between the various blocks, i.e. between POS and sim v, between sim v and C, etc (see the ugly red lines in the plot).
I’ve been struggling with geom_vline with no luck.
Alternatively, I’d like to add blank space between the blocks.

2) If I print this plot in grayscale, I can’t distinguish the different blocks. I’m trying to force a different palette with:

scale_colour_manual( values=c("black","darkgray","gray","white") )

Again, no luck, the plot doesn’t change at all.

What would you suggest to do?

Answer 1

Would this work for you?

require(ggplot2)
mtcars$cyl2<- ifelse(mtcars$cyl > 4, c('A'), c('B')) 
p <- ggplot(mtcars, aes(factor(cyl), mpg))
p + geom_boxplot() + facet_grid(. ~ cyl2, scales = "free", space = "free")

would give something like this,