I have a variable ceroonce which is number of schools per county (integers) in 2011. When I plot it with
ggplot(escuelas, aes(x=ceroonce, y=ceroonce))+geom_boxplot()
There are no fancy statistics happening here.
boxplot is simply assuming that since you've given it a single vector, that you want a single box in your boxplot.
geom_histogram simply don't make that assumption.
If you want a bit less typing, you can do this:
qplot(y=escuelas$ceroonce, x= 1, geom = "boxplot")
ggplot2 will automatically create a vector of 1s equal in length to the length of escuelas$ceroonce