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Swimlane line plot for longitudinal trajectories

geom_kodom_line.Rd

Draws one horizontal colored path per subject. Time maps to x, subject identity maps to id (which the stat converts to integer lane positions on the y axis), and a measured value maps to colour. The colour transitions smoothly between consecutive observations via interpolated sub-segments.

Usage

geom_kodom_line(
  mapping = NULL,
  data = NULL,
  stat = StatKodomLine,
  position = "identity",
  ...,
  sort_by = "none",
  n_max = Inf,
  show_points = TRUE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by ggplot2::aes().

data

A data frame. If NULL, inherits from the plot.

stat

The stat to use. Defaults to StatKodomLine.

position

Position adjustment, almost always "identity".

...

Other arguments passed to ggplot2::layer().

sort_by

Lane ordering. One of "none" (default), "mean", "mean_asc", "first", "last" — all refer to the colour variable.

n_max

Maximum number of subjects to display. A random sample is taken when exceeded. Default Inf (all subjects).

show_points

If TRUE (default), draws a point at every observation. Set to FALSE, or map shape = NA / size = 0, to suppress points.

na.rm

If TRUE, silently remove rows with missing required aesthetics.

show.legend

Logical. Should this layer appear in the legend?

inherit.aes

If FALSE, overrides the default aesthetics.

Value

A ggplot2 layer object.

Details

Lane ordering is controlled by sort_by. With many subjects, consider suppressing y-axis labels via theme(axis.text.y = element_blank()).

Aesthetics

Required aesthetics are shown in bold. size and linewidth are intentionally independent: each controls a different graphical element.

  • x — time variable (numeric or Date)

  • id — subject identifier; determines lane position on the y axis

  • colour — color of both the connecting path and the point border

  • fill — point interior color for filled shapes (21–25); no effect on path

  • size — point size only; set to NA or 0 to suppress points

  • linewidth — path width only; does not affect observation points

  • alpha — transparency applied to both path and points

  • shape — point shape (default 19). Set to NA to suppress points.

  • stroke, linetype — point border width / path line type

Examples

# \donttest{
library(ggplot2)
df <- data.frame(
  subject_id = rep(1:5, each = 4),
  time = rep(1:4, 5),
  visit_month = rep(1:4, 5),
  value = rep(1:4, 5),
  hba1c = rep(1:4, 5),
  arm = rep(c("Treatment", "Control"), c(12, 8))
)
ggplot(df, aes(x = time, id = subject_id, colour = hba1c)) +
  geom_kodom_line(sort_by = "mean", n_max = 50) +
  scale_colour_kodom() +
  theme_kodom()

# }