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)CoordTern
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.coord_tern returns a CoordTern ggprotoCoordTern (inherits from CoordCartesian, Coord, ggproto) of length 8.