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.coord_tern(T = getOption("tern.default.T"), L = getOption("tern.default.L"),
R = getOption("tern.default.R"), xlim = c(0, 1), ylim = c(0, 1),
Tlim = NULL, Llim = NULL, Rlim = NULL, clockwise)
'tern.default.T'
)'tern.default.L'
)'tern.default.R'
)axis.tern.clockwise
.coord_tern
returns a ternary coordinate system object.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.
Abovementioned limitations include the types of geometries which can be used (ie approved geometries),
or modifications to required aesthetic mappings. One such essential patch is, for approved geometries previously
requiring x
and y
coordinates, now require an additional z
coordinate, and,
geom_segment
goes one step further in that it requires both an additional
z
and zend
coordinate mappings.
In essence, the required aesthetics are the product between what is required of the 'layer' and what is required of the 'coordinate system'. }