Question

I want to make a radial stacked barchart. I have something like this:

ggplot(diamonds, aes(clarity, fill= cut)) +  geom_bar()  + coord_polar()

which yields a plot like this:

However this is very crowded. Is there a way to change the axes so that this barchart is hollow? I would want zero to start not at the center of the circle but, say, 1/3 or 1/2 of the radius from the center. Any ideas about that?

Answer 1

You can tell coord_plot to expand slightly – this puts a small hole in the middle:

ggplot(diamonds, aes(clarity, fill= cut)) +  
    geom_bar()  + 
    coord_polar(expand=TRUE)

Then you can control the y scale expansion (with the argument expand=... to scale_y_continuous(...). Unfortunately I think the expansion is symmetrical, i.e. if you add space at the bottom (i.e. in the middle, you also add it at the top (i.e. the outside):

ggplot(diamonds, aes(clarity, fill= cut)) +  
    geom_bar()  + 
    coord_polar(expand=TRUE) + 
    scale_y_continuous(expand=c(0.5, 0))