Ternary Plot

Produces a ternary plot.

Usage

ternary_plot(x, y, z, ...)

# S4 method for class 'numeric,numeric,numeric'
ternary_plot(
  x,
  y,
  z,
  center = FALSE,
  scale = FALSE,
  xlim = NULL,
  ylim = NULL,
  zlim = NULL,
  xlab = NULL,
  ylab = NULL,
  zlab = NULL,
  main = NULL,
  sub = NULL,
  ann = graphics::par("ann"),
  axes = TRUE,
  frame.plot = axes,
  panel.first = NULL,
  panel.last = NULL,
  ...
)

# S4 method for class 'ANY,missing,missing'
ternary_plot(
  x,
  xlim = NULL,
  ylim = NULL,
  zlim = NULL,
  xlab = NULL,
  ylab = NULL,
  zlab = NULL,
  main = NULL,
  sub = NULL,
  ann = graphics::par("ann"),
  axes = TRUE,
  frame.plot = axes,
  panel.first = NULL,
  panel.last = NULL,
  ...
)

Arguments

x, y, z

A numeric vector giving the x, y and z ternary coordinates of a set of points. If y and z are missing, an attempt is made to interpret x in a suitable way (see grDevices::xyz.coords()).

...

Other graphical parameters may also be passed as arguments to this function.

center

A logical scalar: should the data be centered?

scale

A logical scalar: should the data be scaled?

xlim

A length-three numeric vector giving the x limits in the range \([0,1]\).

ylim

A length-three numeric vector giving the y limits in the range \([0,1]\).

zlim

A length-three numeric vector giving the z limits in the range \([0,1]\).

xlab, ylab, zlab

A character string giving a label for the x, y and z axes.

main

A character string giving a main title for the plot.

sub

A character string giving a subtitle for the plot.

ann

A logical scalar: should the default annotation (title and x, y and z axis labels) appear on the plot?

axes

A logical scalar: should axes be drawn on the plot?

frame.plot

A logical scalar: should a box be drawn around the plot?

panel.first

An an expression to be evaluated after the plot axes are set up but before any plotting takes place. This can be useful for drawing background grids.

panel.last

An expression to be evaluated after plotting has taken place but before the axes, title and box are added.

Value

ternary_plot() is called it for its side-effects: it results in a graphic being displayed. Invisibly returns a list with the components:

x	A numeric vector of x values.
y	A numeric vector of y values.
z	A numeric vector of z values.
center	A numeric vector giving the center.
scale	A numeric vector giving the scale factor.

See also

Other graphical elements: ternary_axis(), ternary_box(), ternary_grid(), ternary_pairs(), ternary_title()

Author

N. Frerebeau

Examples

## Blank plot
ternary_plot(NULL)


## Compositional data
coda <- data.frame(
  X = c(20, 60, 20, 1/3),
  Y = c(20, 20, 60, 1/3),
  Z = c(60, 20, 20, 1/3)
)

## Ternary plot
ternary_plot(coda, pch = 16, col = "red")


## Add a grid
ternary_plot(coda, panel.first = ternary_grid(5, 10))


## Zoom
ternary_plot(coda, ylim = c(0, 0.4, 0), zlim = c(0, 0, 0.4),
             panel.first = ternary_grid())

ternary_plot(coda, xlim = c(0, 0.4, 0), zlim = c(0, 0, 0.4),
             panel.first = ternary_grid())

ternary_plot(coda, xlim = c(0.4, 0, 0), ylim = c(0, 0.4, 0),
             panel.first = ternary_grid())


## Color according to a supplementary variable
## Data from Aitchison 1986
col <- grDevices::colorRampPalette(c("red", "blue"))(nrow(arctic))
ternary_plot(arctic, panel.first = ternary_grid(), pch = 16, col = col)