Add marks to an scplot object

Marks specific points in an scplot object.

add_marks(
  object,
  case = 1,
  positions,
  color = "red",
  size = 1,
  shape = 1,
  variable = ".dvar"
)

Arguments

object

An scplot object (class scplot) returned from the scplot() function.

case

Numerical vector with the case number or character string. case = "all" for all cases.

positions

Either a vector indicating the points to be highlighted or a character string with a logical expression (e.g. values < mean(values)) indicating the points to be highlighted. Alternatively, an object of class sc_outlier returned from the scan::outlier() function can be used to mark the detected outliers. A list of such vectors or expressions can also be provided to add marks for multiple cases at once.

color

A character string or a number defining the color of an element.

size

Text size relative to the base text size.

shape

Number. See pch graphical parameter on par help page par().

variable

Name of the dataline variable to apply the style.

Value

An object of class scplot (see scplot()) with changed element marks.

Details

Marks are visualized as points on top of the existing plot. Multiple marks can be added by calling add_marks() multiple times.

If positions is an object returned from an outlier analysis via outlier(), the corresponding outliers are marked. If positions is a list, marks are added for each case in the list. The variable argument specifies the variable on which the marks are applied. By default, the variable .dvar is used. If multiple cases are plotted, the case argument specifies for which case(s) the marks are added.

Author

Juergen Wilbert

Examples

library(scan)
#> scan 0.67.2 (2026-01-12)
#> Type 'import_scdf()' to start the import helper.
p1 <- scplot(exampleA1B1A2B2$Moritz) |> add_marks(positions = c(1,5,10,14))
p1 <- scplot(Huber2014) |> add_marks(positions = outlier(Huber2014))