multi-panel plots in ggplot2: scales that are "free and equal"?

Question

I have issued the following command to a ggplot figure:

facet_wrap(~variable,scales="free")

but I also want for the x and y scales to be equal for each panel (while the limits vary from panel to panel). Is this possible in ggplot2?

Answer 1

If you use facet_grid, you can specify space='free'. I think this is what you want.

require(ggplot2)

x = 1:9
group = rep(1:3, each=3)
data = data.frame(x, group)
qplot(x, x, data=data) + facet_grid(~group, scales='free', space='free')