Scatterplots in ggplot2
You will learn the layered syntax of ggplot2 for scatterplots in this section. It also demonstrates how regression lines can be added (compared with the base-R syntax shown in the introductory video).
Scatter plots with multiple groups
Change the point color/shape/size automatically
In the R code below, point shapes, colors and sizes are controlled by the levels of the factor variable cyl :
# Change point shapes by the levels of cyl ggplot(mtcars, aes(x=wt, y=mpg, shape=cyl)) + geom_point() # Change point shapes and colors ggplot(mtcars, aes(x=wt, y=mpg, shape=cyl, color=cyl)) + geom_point() # Change point shapes, colors and sizes ggplot(mtcars, aes(x=wt, y=mpg, shape=cyl, color=cyl, size=cyl)) + geom_point()