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 available on CRAN, but you can also install the latest version from github with devtools.

devtools::install_github("Freguglia/ggfocus") # Latest version
install.packages("ggfocus") # CRAN version


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)

You can also use the usual ggplot2 grammar + to add scales with the family of function scale_*_focus(). These two uses are equivalent, read the vignette for more information.


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, ggmap.


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)

Contributing and Bug Reports

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ggfocus documentation built on Jan. 8, 2019, 1:04 a.m.