Facet labels and order

Intermediate Data Visualization with ggplot2

Rick Scavetta

Founder, Scavetta Academy

A new dataframe

# Plot
p <- ggplot(msleep2, aes(bodywt_log,
                         brainwt_log)) +
  geom_point(alpha = 0.6, shape = 16) +
  coord_fixed()

p

A new dataframe, with facets

p +
  facet_grid(rows = vars(vore))

A new dataframe, with facets

p +
  facet_grid(rows = vars(vore))

Poor labels and order

p +
  facet_grid(rows = vars(vore))

Two typical problems with facets:

Poorly labeled (e.g. non descriptive)
Wrong or inappropriate order

Poor labels and order

p +
  facet_grid(rows = vars(vore))

Solutions:

Easy: Add labels in ggplot
Better: Relabel and rearrange factor variables in your dataframe

The labeller argument

# Default is to label the value
p +
  facet_grid(rows = vars(vore), 
             labeller = label_value)

Using label_both adds the variable name

# Print variable name also
p +
  facet_grid(rows = vars(vore), 
               labeller = label_both)

Two variables on one side

p +
  facet_grid(rows = vars(vore, 
                         conservation))

Using label_context avoids ambiguity

p +
  facet_grid(rows = vars(vore,
                         conservation),
               labeller = label_context)

Use rows and columns when appropriate

p +
  facet_grid(rows = vars(vore), 
             cols = vars(conservation),
             labeller = label_context)

Use rows and columns when appropriate

p +
  facet_grid(rows = vars(vore), 
             cols = vars(conservation))

Use rows and columns when appropriate

Relabeling and reordering factors

msleep2$conservation <- fct_recode(msleep2$conservation,
                                   Domesticated = "domesticated",
                                   `Least concern` = "lc",
                                   `Near threatened` = "nt",
                                   Vulnerable = "vu",
                                   Endangered = "en")

msleep2$vore = fct_recode(msleep2$vore,
                          Carnivore = "carni",
                          Herbivore = "herbi",
                          Insectivore = "insecti",
                          Omnivore = "omni")

Reinitialize plot with new labels

# Plot
p <- ggplot(msleep2, aes(bodywt_log,
                         brainwt_log)) +
  geom_point(alpha = 0.6, shape = 16) +
  coord_fixed()

p +
  facet_grid(rows = vars(vore), 
             cols = vars(conservation))

Reinitialize plot with new labels

Changing the order of levels

# Change order of levels:
msleep2$conservation = fct_relevel(msleep2$conservation,
                                   c("Domesticated",
                                     "Least concern",
                                     "Near threatened",
                                     "Vulnerable",
                                     "Endangered"))

Reinitialize plot with new order

Let's practice!

Intermediate Data Visualization with ggplot2