coord_tern: Ternary Coordinate System

Description

coord_tern is a function which creates a transformation mechanism between the ternary system, and, the cartesian system. It inherits from the fixed coordinate system, employing fixed ratio between x and y axes once transformed.

Usage

coord_tern(T = "x", L = "y", R = "z", xlim = c(0, 1),
    ylim = c(0, 1), Tlim = NULL, Llim = NULL, Rlim = NULL,
    clockwise)

Arguments

the Top Mapping (default x)

the Left Mapping (default y)

the Right Mapping (default z)

xlim

the range of x in the cartesian space

ylim

the range of y in the cartesian space

Tlim

the range of T in the ternary space

Llim

the range of L in the ternary space

Rlim

the range of R in the ternary space

clockwise

(Depreciated) logical (default FALSE) indicating whether the precession of axes is clockwise (TRUE) or counter-clockwise (FALSE).

Value

ternary coordinate system object.

Details

It is important to note that once the coord_tern() coordinate system has been applied, the base plot object is no longer strictly a ggplot object, rather, a ggtern object where several patches have been applied to facilitate correct plotting, including, some limitations on the types of geometries which can be used. One such essential patch is, for approved geometries previously requiring x and y coordinates, now require an additional z coordinate. geom_segment goes one step further in that it requires both an additional z and zend coordinate mappings.