12.27 三元图

Ternary 使用基础图形库，而 ggtern 使用 ggplot2 绘制

library(ggtern)
library(ggalt)
data("Fragments")
ggtern(Fragments, aes(
  x = Qm, y = Qp, z = Rf + M,
  fill = GrainSize, shape = GrainSize
)) +
  geom_encircle(alpha = 0.5, size = 1) +
  geom_point() +
  labs(
    title = "Example Plot",
    subtitle = "using geom_encircle"
  ) +
  theme_bw() +
  theme_legend_position("tr")