position_brain: Arrange brain atlas views

In ggseg: Plotting Tool for Brain Atlases

Arrange brain atlas views

Description

Controls how an atlas's hemispheres and views are arranged in the plot – side by side, stacked, or in a grid – and can zoom each view in on the regions you care about. Pass the result to the 'position' argument of [geom_brain()] (or [annotate_brain()]).

Usage

position_brain(
  position = "horizontal",
  nrow = NULL,
  ncol = NULL,
  views = NULL,
  zoom = NULL,
  zoom_pad = 0.05
)

Arguments

position	Formula describing the rows ~ columns organisation for cortical atlases (e.g., 'hemi ~ view'). For subcortical/tract atlases, can be "horizontal", "vertical", or a formula with 'type ~ .' where type is extracted from view names like "axial_1" -> "axial".
nrow	Number of rows for grid layout. If NULL (default), calculated automatically. Only used for subcortical/tract atlases when position is not a formula.
ncol	Number of columns for grid layout. If NULL (default), calculated automatically. Only used for subcortical/tract atlases when position is not a formula.
views	Character vector specifying which views to include and their order. If NULL (default), all views are included in their original order. Only applies to subcortical/tract atlases.
zoom	Controls per-view zoom. 'NULL'/'FALSE' (default) draws each view at full extent. 'TRUE' zooms each view onto its focus regions; a character vector names the focus regions explicitly.
zoom_pad	Fractional padding added around the focus window when 'zoom' is active. Defaults to '0.05' (5%).

Value

A layout specification to hand to [geom_brain()]'s 'position' argument.

Examples

library(ggplot2)

# Cortical atlas with formula
ggplot() +
  geom_brain(
    atlas = dk(), aes(fill = region),
    position = position_brain(. ~ view + hemi),
    show.legend = FALSE
  )

ggplot() +
  geom_brain(
    atlas = dk(), aes(fill = region),
    position = position_brain(view ~ hemi),
    show.legend = FALSE
  )

ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(nrow = 2)
  )

ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(
      views = c("sagittal", "axial_3", "coronal_2"),
      nrow = 1
    )
  )

ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(type ~ .)
  )

ggseg documentation built on June 22, 2026, 9:09 a.m.