R: How do I use coord_cartesian on facet_grid with free-ranging axis

Question

Consider some facet_grid plot

mt <- ggplot(mtcars, aes(mpg, wt, colour = factor(cyl))) + geom_point() 
mt + facet_grid(vs ~ am, scales = \"fr         


        

Answer 1

So, this is an old question, but I wanted to share a way that I found. The simplest seems to be to add artificial points to your data, e.g. at the lower left and top right of your data for each plot. Put this information into a separate data frame, then add it to the plot with geom_point using the parameter alpha=0 to make the points invisible. Set the scaling of the axis in facet_wrap to "free_x" or "free_y", depending on what you need.

Now ggplot scales every facet separately to accommodate the invisible points that you added. A bit hacky, but works nicely.