stat_changepoint: Changepoint detection stat

In ggchangepoint: Combines Changepoint Analysis with 'ggplot2'

Changepoint detection stat

Description

Runs changepoint detection inside the ggplot pipeline. Useful for quick exploration: ggplot(df, aes(t, y)) + geom_line() + stat_changepoint(method = "pelt"). Draws vertical lines at detected changepoint locations.

Usage

stat_changepoint(
  mapping = NULL,
  data = NULL,
  geom = "vline",
  position = "identity",
  ...,
  method = "pelt",
  change_in = "mean",
  na.rm = FALSE,
  show.legend = NA
)

Arguments

mapping	Aesthetic mappings.
data	A data frame.
geom	The geometric object to use (default: "vline"). The stat computes a single xintercept per changepoint and drops x/y, so "vline" is the geom that fits. A geom needing x/y ("point", and "rug", which consumes x/y rather than xintercept) errors for that reason. inherit.aes is fixed at TRUE here: the stat re-detects on the plot's own data, so the panel's x/y mapping is what it reads.
position	Position adjustment.
...	Other arguments passed to the geom.
method	Detection method (passed to cpt_detect).
change_in	What to detect change in (passed to cpt_detect).
na.rm	If FALSE, missing values are removed.
show.legend	Whether to show legend.

Value

A ggplot layer.

See Also

Other ggplot2 layers: geom_changepoint(), geom_cpt_ci(), geom_cpt_event(), geom_cpt_label(), geom_cpt_region(), geom_cpt_segment(), ggchangepoint-ggproto, stat_cpt_region()

Examples

library(ggplot2)
set.seed(2026)
d <- data.frame(t = 1:100, y = c(rnorm(50), rnorm(50, 4)))
ggplot(d, aes(t, y)) + geom_line() +
  stat_changepoint(method = "pelt", colour = "blue")

ggchangepoint documentation built on Nov. 5, 2026, 9:06 a.m.