ggplot2 Cheat Sheet:
Two Variables: Continuous Functions

library(ggplot2)

Area Plot

p <- ggplot(economics, aes(date, unemploy))
p <- p + geom_area()
print(p)

Line Plot

Data points are joined in ascending order of their x-value.

p <- ggplot(economics, aes(date, unemploy))
p <- p + geom_line()
print(p)

Step Plot

p <- ggplot(women, aes(height, weight))
p <- p + geom_step()
print(p)