Create a grid of penguin glyphs from a data frame

Visualizes multiple penguins as a grid of glyphs, automatically normalizing measurements to appropriate visual ranges. This function creates a complete plot with legend showing the mapping between data and visual features.

Usage

penguin_glyphs(
  data,
  bill_len = "bill_len",
  bill_dep = "bill_dep",
  flipper_len = "flipper_len",
  body_mass = "body_mass",
  species = "species",
  sex = "sex",
  ncol = 5,
  main = "Penguin Glyphs",
  legend = list(loc = "topleft", horiz = FALSE),
  ref = NULL,
  col = penguin_colors(),
  cex.lab = 1
)

Arguments

data

Data frame with penguin measurements (typically datasets::penguins)

bill_len

Column name for bill length (default "bill_len")

bill_dep

Column name for bill depth (default "bill_dep")

flipper_len

Column name for flipper length (default "flipper_len")

body_mass

Column name for body mass (default "body_mass")

species

Column name for species (default "species")

sex

Column name for sex (default "sex")

ncol

Number of columns in grid (default 5)

main

Plot title (default "Penguin Glyphs")

legend

List with legend parameters: loc for location, one of the keywords "topleft", "top", "topright", "left", "right", "bottomleft", "bottom" or "bottomright", and horiz for horizontal layout (TRUE/FALSE). Default is list(loc = "topleft", horiz = FALSE)

ref

Reference data frame, whose ranges of the measurement variables determine how they are scaled. With the default, NULL, the ranges are those of the full datasets::penguins data, so that a given penguin is drawn the same way in any subset. A variable not found there is scaled by its range in data. Use ref = data to scale all variables relative to the rows being plotted.

col

Named vector of body colors, with species as names. See penguin_colors().

cex.lab

Character expansion for the ID labels in the glyphs (default 1)

Value

NULL (creates a plot)

Details

Each continuous variable is normalized to a scale of 0.7 to 1.3, relative to its range in ref, to ensure visual differences are apparent but not extreme. Row names from the data frame are displayed as IDs within each penguin glyph. Missing values are shown as described in draw_penguin().

The legend is placed outside the grid of glyphs, on the side given by legend$loc. The grid cells are square, so there is usually spare room either beside the grid or above and below it. For a corner position such as "topleft", the legend goes beside or above the grid, whichever leaves more room for the glyphs.

See also

penguin_points() to use the glyphs as point symbols in another plot

Examples

# Load the penguins dataset
data(penguins, package = "datasets")

# Visualize first 5 penguins in each species
which <- outer(1:5, c(0, 152, 277), FUN ="+") |> c()
penguin_glyphs(penguins[which,])


# Sample random penguins
set.seed(42)
sampled_rows <- sample(1:nrow(penguins), size = 20)
penguin_glyphs(penguins[sampled_rows, ], main = "Random Penguin Glyphs")


# Look at specific outliers, among the penguins with complete data.
# Renumbering the rows gives the same case numbers as in heplots::peng
peng <- na.omit(penguins)
rownames(peng) <- NULL
outliers <- c(10, 35, 283)
penguin_glyphs(peng[outliers,], main = "Notable Penguins")


# Custom legend position
penguin_glyphs(penguins[sampled_rows, ],
               legend = list(loc = "bottom", horiz = FALSE))