Many times during data analysis, one may want to visualize data for a specific subgroup of observations. While ggplot is great for data visualization in general, constructing graphics that focus on those subgroups may need very troublesome manipulation of data and graphical scales (for example colors), i.e. setting low alpha for unimportant observations, coloring things in a way that highlights the focus subgroup, etc.

ggfocus allows you to build graphics that focus on those specific subgroups by doing the scale manipulation automatically while keeping all the flexibility from ggplot. The idea behind this approach is from this issue from tidyverse/ggplot2.

Installing ggfocus

The package is not available in CRAN (yet), but you can install it from github with devtools.



ggfocus implements the ggfocus() function.

ggfocus(p, var, focus_levels, focus_aes = c("color", "alpha"),
  color_focus = NULL, color_other = "black", alpha_focus = 1,
  alpha_other = 0.05)


Using the gapminder dataset, first we create our ggplot

p <- ggplot(gapminder, aes(x=log(gdpPercap), y=lifeExp, group=country)) + geom_line()

Now we can use ggfocus() to highlight European countries only.

ggfocus(p, continent, "Europe")

We can also highlight countries

ggfocus(p, country, c("Brazil","Argentina"), color_focus = c("Green","Blue"))

Interaction with other extensions

Because ggfocus() retuns a modified ggplot object, other ggplot extensions can used with it, for example, gganimate.

p <- ggplot(gapminder, aes(x=log(gdpPercap), y=lifeExp, size=pop, frame=year)) + geom_point()
focus_p <- ggfocus(p,country,c("Brazil","Argentina"), color_focus = c("Green","Blue"))

Using ggfocus with ggmaps


wm <- map_data("world")
p <- ggplot(wm, aes(x=long, y = lat, group = group)) + geom_polygon(color="black") + theme_void()
ggfocus(p, region, c("Brazil","India","Italy","Canada"),focus_aes = c("fill","alpha"),
        color_focus = "blue", alpha_other = 0.15) + guides(fill=FALSE)

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ggfocus documentation built on May 29, 2018, 5:04 p.m.