I have a faceted plot that forms an n x m
grid. By design, the last (bottom-right) cell is always empty, so I'd like to utilize the extra space by adding another ggplot object. My current solution relies on low-level viewport
approach, which is not very elegant and requires some hard-coding for position and size.
Instead, I assume the empty space is reachable in some other fashion, probably with gridExtra
?
Here's a minimal example for n=m=2
. Note that the edges are not aligned properly, so some extra work is required to manually adjust viewport's parameters, which is a pain, especially if (n, m)
change afterwards.
library(ggplot2)
library(grid)
p <- qplot(displ, hwy, data = mpg[mpg$cyl != 5, ]) +
facet_wrap(~ cyl, nrow=2)
q <- qplot(date, unemploy, data = economics, geom = "line") +
labs(x = NULL, y = NULL)
p
print(q, vp=viewport(0.75, 0.275, 0.45, 0.45))