Question

i’m looking for some help in creating a faceted plot with angeled x-axis tick labels, which is probably best explained by the following example:

require(ggplot2)
df <- data.frame(group=factor(c('sex','sex','race','race')), variable=c('Female','Male','White','African American'), value=1:4)
p <- ggplot(aes(x=variable, y=value), data=df) 
p <- p + geom_line()
p <- p + facet_grid(. ~ group, scale="free")
p <- p + opts(axis.text.x=theme_text(angle=45,hjust=1,vjust=1))
ggsave(p, file='faceted.pdf', width=6, height=4)

which produces this figure where the x-ticks on the right are misaligned:

it seems that the problem is introduced when using scale="free" in the facet_grid and is related to the varying tick label length.

any suggestions are greatly appreciated.

Answer 1

Looks like a bug: https://github.com/hadley/ggplot2/issues/221 that has apparently been fixed in ggplot2 0.9 and later.

> help(package='ggplot2')
                Information on package ‘ggplot2’    
Description:
Package:            ggplot2
Type:               Package
Title:              An implementation of the Grammar of Graphics
Version:            0.8.9

(Too bad for me!)

Bug reproducible with:

qplot(reorder(model, hwy), hwy, data=mpg) +
    facet_grid(. ~ manufacturer, scales="free") +
    opts(axis.text.x = theme_text(angle=90))