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(Tlim = NULL, Llim = NULL, Rlim = NULL, expand = TRUE)coord_tern returns a CoordTern ggproto
the range of T in the ternary space
the range of L in the ternary space
the range of R in the ternary space
If TRUE, the default, adds a small expansion factor to
the limits to ensure that data and axes don't overlap. If FALSE,
limits are taken exactly from the data or xlim/ylim.
Giving a logical vector will separately control the expansion for the four
directions (top, left, bottom and right). The expand argument will be
recycled to length 4 if necessary. Alternatively, can be a named logical
vector to control a single direction, e.g. expand = c(bottom = FALSE).
ggtern:::rd_aesthetics("coord", "tern")
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 each 'layer' and what is required of the 'coordinate system'.
Nicholas Hamilton