Restrict ordination data to the convex hulls of both matrix factors

As used in a ggplot2 vignette, this stat layer restricts a dataset with x and y variables to its convex hull. The biplot extension restricts each matrix factor to its own hull. The conical parameter controls whether the origin is included in the calculation, though note that the result is not the (unbounded) conical hull.

stat_chull(
  mapping = NULL,
  data = NULL,
  geom = "polygon",
  position = "identity",
  conical = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

stat_rows_chull(
  mapping = NULL,
  data = NULL,
  geom = "polygon",
  position = "identity",
  conical = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

stat_cols_chull(
  mapping = NULL,
  data = NULL,
  geom = "polygon",
  position = "identity",
  conical = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

Arguments

mapping	Set of aesthetic mappings created by `aes()` or `aes_()`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
data	The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot()`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify()` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame`, and will be used as the layer data. A `function` can be created from a `formula` (e.g. `~ head(.x, 10)`).
geom	The geometric object to use display the data
position	Position adjustment, either as a string, or the result of a call to a position adjustment function.
conical	Logical; whether to include the origin when calculating the hull. Defaults to `FALSE`.
show.legend	logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes. It can also be a named logical vector to finely select the aesthetics to display.
inherit.aes	If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders()`.
...	Additional arguments passed to `ggplot2::layer()`.

Format

An object of class StatChull (inherits from Stat, ggproto, gg) of length 3.

An object of class StatRowsChull (inherits from StatChull, Stat, ggproto, gg) of length 2.

An object of class StatColsChull (inherits from StatChull, Stat, ggproto, gg) of length 2.

Biplot layers

ggbiplot() uses ggplot2::fortify() internally to produce a single data frame with a .matrix column distinguishing the subjects ("rows") and variables ("cols"). The stat layers stat_rows() and stat_cols() simply filter the data frame to one of these two.

The geom layers geom_rows_*() and geom_cols_*() call the corresponding stat in order to render plot elements for the corresponding factor matrix. geom_dims_*() selects a default matrix based on common practice, e.g. points for rows and arrows for columns.