gg_density: Produce ggplot of densities from distributional objects in 1...

In weird: Functions and Data Sets for "That's Weird: Anomaly Detection Using R" by Rob J Hyndman

Produce ggplot of densities from distributional objects in 1 or 2 dimensions

Description

Produce ggplot of densities from distributional objects in 1 or 2 dimensions

Usage

gg_density(
  object,
  prob = seq(9)/10,
  hdr = NULL,
  show_points = FALSE,
  show_mode = FALSE,
  show_anomalies = FALSE,
  colors = c("#0072b2", "#D55E00", "#009E73", "#CC79A7", "#E69F00", "#56B4E9", "#F0E442",
    "#333333"),
  alpha = NULL,
  jitter = FALSE,
  ngrid = 501
)

Arguments

object	distribution object from the distributional package or dist_kde()
prob	Probability of the HDRs to be drawn.
hdr	Character string describing how the HDRs are to be shown. Options are "none", "fill", "points" and "contours" (the latter only for bivariate plots). If NULL, then "none" is used for univariate distributions and "contours" for bivariate.
show_points	If TRUE, then individual observations are plotted.
show_mode	If TRUE, then the mode of the distribution is shown as a point.
show_anomalies	If TRUE, then the observations with surprisal probabilities less than 0.005 (using a GPD approximation) are shown in black.
colors	Color palette to use. If there are more than length(colors) distributions, they are recycled. Default is the Okabe-Ito color palette.
alpha	Transparency of points. Ignored if show_points is FALSE. Defaults to min(1, 500/n), where n is the number of observations plotted.
jitter	For univariate distributions, when jitter is TRUE and show_points is TRUE, a small amount of vertical jittering is applied to the observations. Ignored for bivariate distributions.
ngrid	Number of grid points to use for the density function.

Details

This function produces a ggplot of a density from a distributional object. For univariate densities, it produces a line plot of the density function, with an optional ribbon showing some highest density regions (HDRs) and/or the observations. For bivariate densities, it produces ah HDR contour plot of the density function, with the observations optionally shown as points. The mode can also be drawn as a point. The combination of hdr = "fill", show_points = TRUE, show_mode = TRUE, and prob = c(0.5, 0.99) is equivalent to showing HDR boxplots.

Value

A ggplot object.

Author(s)

Rob J Hyndman

Examples

# Univariate densities
kde <- dist_kde(c(rnorm(500), rnorm(500, 4, .5)))
gg_density(kde,
  hdr = "fill", prob = c(0.5, 0.95), color = "#c14b14",
  show_mode = TRUE, show_points = TRUE, jitter = TRUE
)
c(dist_normal(), kde) |>
  gg_density(hdr = "fill", prob = c(0.5, 0.95))
# Bivariate density
tibble(y1 = rnorm(5000), y2 = y1 + rnorm(5000)) |>
  dist_kde() |>
  gg_density(show_points = TRUE, alpha = 0.1, hdr = "fill")

weird documentation built on Jan. 27, 2026, 9:06 a.m.