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Add penguin glyphs to a plot

Source: R/penguin_points.R
penguin_points.Rd

Draws a penguin glyph at each of the points (x, y) in an existing plot, in the manner of graphics::points(). The features of each glyph are taken from the corresponding row of data.

Usage

penguin_points(
  x,
  y,
  data,
  bill_len = "bill_len",
  bill_dep = "bill_dep",
  flipper_len = "flipper_len",
  body_mass = "body_mass",
  species = "species",
  sex = "sex",
  ref = NULL,
  size = 0.4,
  id = FALSE,
  col = penguin_colors(),
  cex.lab = 0.8,
  ...
)

Arguments

x, y

Coordinates of the glyphs, in the units of the current plot. Each should have one value for each row of data.

data

Data frame with penguin measurements, one row for each point

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")

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.

size

Height of a glyph in inches, for a penguin with all measurements at the middle of their ranges

id

Labels to display in the bodies of the glyphs: TRUE to use the row names of data, or a vector of labels. The default, FALSE, gives no labels.

col

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

cex.lab

Character expansion for the id labels (default 0.8)

...

Other arguments passed to draw_penguin(), such as lwd

Value

NULL, invisibly. Called for its side effect of adding glyphs to a plot.

Details

Each continuous variable is normalized to a scale of 0.7 to 1.3, relative to its range in ref. Rows with a missing x or y are not drawn. Other missing values are shown as described in draw_penguin().

See also

penguin_legend() to add a species legend; penguin_glyphs() for a grid display.

Examples

data(penguins, package = "datasets")
set.seed(42)
peng <- penguins[sample(nrow(penguins), 30), ]

# Glyphs as the point symbols in a scatterplot
plot(body_mass ~ flipper_len, data = peng, type = "n",
     xlab = "Flipper length (mm)", ylab = "Body mass (g)")
penguin_points(peng$flipper_len, peng$body_mass, peng)
penguin_legend("topleft", peng$species)


# In a plot of the first two principal components
peng <- na.omit(penguins)
pca <- prcomp(peng[, 3:6], scale. = TRUE)
show <- sample(nrow(peng), 40)
plot(pca$x[, 1:2], type = "n")
penguin_points(pca$x[show, 1], pca$x[show, 2], peng[show, ], size = 0.5)
penguin_legend("top", peng$species, horiz = TRUE)