Ternary Coordinates

Computes ternary coordinates.

Usage

coordinates_ternary(x, y, z, ...)

# S4 method for class 'numeric,numeric,numeric'
coordinates_ternary(
  x,
  y,
  z,
  center = FALSE,
  scale = FALSE,
  missing = getOption("isopleuros.missing")
)

# S4 method for class 'ANY,missing,missing'
coordinates_ternary(
  x,
  xlab = NULL,
  ylab = NULL,
  zlab = NULL,
  center = FALSE,
  scale = FALSE,
  missing = getOption("isopleuros.missing")
)

Arguments

x, y, z

A numeric vector giving the x, y and z cartesian 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()).

...

Currently not used.

center

A logical scalar or a numeric vector giving the center.

scale

A logical scalar or a length-one numeric vector giving a scaling factor.

missing

A logical scalar: should missing values be replaced with zeros before the computation proceeds? If FALSE (the default), incomplete cases are removed.

xlab, ylab, zlab

A character string specifying the names for the x, y and z variables to be extracted.

Value

A list with the components:

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

See also

Other coordinates: coordinates_cartesian()

Author

N. Frerebeau

Examples

## Compositional data
coda <- data.frame(
  x = c(1, 0, 0, 1/3),
  y = c(0, 1, 0, 1/3),
  z = c(0, 0, 1, 1/3)
)

## Ternary coordinates
(tern <- coordinates_ternary(coda))
#> $x
#> [1] 0.0 1.0 0.5 0.5
#> 
#> $y
#> [1] 0.0000000 0.0000000 0.8660254 0.2886751
#> 
#> $center
#> [1] 1 1 1
#> 
#> $scale
#> [1] 1
#> 

## Cartesian coordinates
(cart <- coordinates_cartesian(tern))
#> $x
#> [1] 1.0000000 0.0000000 0.0000000 0.3333333
#> 
#> $y
#> [1] 0.0000000 1.0000000 0.0000000 0.3333333
#> 
#> $z
#> [1] 0.0000000 0.0000000 1.0000000 0.3333333
#>