R ggplot2 position_jitter 抖動點以避免過度繪製

position_jitter(width = NULL, height = NULL, seed = NA)

其他位置調整：position_dodge()、position_identity()、position_jitterdodge()、position_nudge()、position_stack()

# Jittering is useful when you have a discrete position, and a relatively
# small number of points
# take up as much space as a boxplot or a bar
ggplot(mpg, aes(class, hwy)) +
  geom_boxplot(colour = "grey50") +
  geom_jitter()


# If the default jittering is too much, as in this plot:
ggplot(mtcars, aes(am, vs)) +
  geom_jitter()


# You can adjust it in two ways
ggplot(mtcars, aes(am, vs)) +
  geom_jitter(width = 0.1, height = 0.1)

ggplot(mtcars, aes(am, vs)) +
  geom_jitter(position = position_jitter(width = 0.1, height = 0.1))


# Create a jitter object for reproducible jitter:
jitter <- position_jitter(width = 0.1, height = 0.1)
ggplot(mtcars, aes(am, vs)) +
  geom_point(position = jitter) +
  geom_point(position = jitter, color = "red", aes(am + 0.2, vs + 0.2))