geom_count: Count the number of observations at each location.

ggplot(mpg, aes(cty, hwy)) +  geom_point()  ggplot(mpg, aes(cty, hwy)) +  geom_count()  # Best used in conjunction with scale_size_area which ensures that # counts of zero would be given size 0. Doesn't make much different # here because the smallest count is already close to 0. ggplot(mpg, aes(cty, hwy)) +  geom_count()  scale_size_area()  # Display proportions instead of counts ------------------------------------- # By default, all categorical variables in the plot form the groups. # Specifying geom_count without a group identifier leads to a plot which is # not useful: d <- ggplot(diamonds, aes(x = cut, y = clarity)) d + geom_count(aes(size = ..prop..)) # To correct this problem and achieve a more desirable plot, we need # to specify which group the proportion is to be calculated over. d + geom_count(aes(size = ..prop.., group = 1)) +  scale_size_area(max_size = 10)  # Or group by x/y variables to have rows/columns sum to 1. d + geom_count(aes(size = ..prop.., group = cut)) +  scale_size_area(max_size = 10) d + geom_count(aes(size = ..prop.., group = clarity)) +  scale_size_area(max_size = 10)