There can be multiple solutions to this problem.
geom_hline
A hacky one is to add a line (probably white, but it depends on your theme) on top of the plot. We can do this using geom_hline
(or geom_vline
if your facets are in rows). This creates an illusion of distance.
library(ggplot2)
ggplot(mpg, aes(displ, cty)) +
geom_point() +
facet_grid(cols = vars(drv)) +
# Add white line on top (Inf) of the plot (ie, betweem plot and facet)
geom_hline(yintercept = Inf, color = "white", size = 4) +
labs(title = "geom_hline")
strip.background
Another solution (as suggested by @atsyplenkov) is to use theme(strip.background = ...)
. There you can specify color of the border. However, this is not a perfect as it cuts border from all the directions (there might be a way to improve this).
ggplot(mpg, aes(displ, cty)) +
geom_point() +
facet_grid(cols = vars(drv)) +
# Increase size of the border
theme(strip.background = element_rect(color = "white", size = 3)) +
labs(title = "strip.background")
theme(strip.background =...)
. See #14186254 – Harrovian