Using different data in ggplot's geom_rug than I use in the rest of the plot

Question

I am having trouble getting geom_rug to plot some data into an existing plot. Here\'s an example plot, where I am comparing some visit day to the magnitude of some measureme

Answer 1

I would try either this:

ggplot(test, aes(x = visit, y = mag)) + geom_point() + 
  geom_rug(data=vac, aes(x = visit,y = NULL))

or perhaps a better option this:

ggplot() + 
  geom_point(data = test,aes(x = visit,y = mag)) + 
  geom_rug(data=vac, aes(x = visit))

Answer 2

You should specify inherit.aes = FALSE in the geom_rug() line, otherwise it inherits y = mag from the main ggplot() call.

ggplot(test, aes(x = visit, y = mag)) + 
  geom_point() + 
  geom_rug(data=vac, aes(x = visit), inherit.aes = F)