2.3 The Basics

In order to create a plot, you:

1. Call the ggplot() function which creates a blank canvas
2. Specify aesthetic mappings, which specifies how you want to map variables to visual aspects. In this case we are simply mapping the displ and hwy variables to the x- and y-axes.
3. You then add new layers that are geometric objects which will show up on the plot. In this case we add geom_point to add a layer with points (dot) elements as the geometric shapes to represent the data.

# create canvas
ggplot(mpg)

# variables of interest mapped
ggplot(mpg, aes(x = displ, y = hwy))

# data plotted
ggplot(mpg, aes(x = displ, y = hwy)) +
  geom_point()

Note that when you added the geom layer you used the addition (+) operator. As you add new layers you will always use + to add onto your visualization.