Aspect ratio I: 1:1 ratios
We can set the aspect ratio of a plot with coord_fixed(), which uses ratio = 1 as a default. A 1:1 aspect ratio is most appropriate when two continuous variables are on the same scale, as with the iris dataset.
All variables are measured in centimeters, so it only makes sense that one unit on the plot should be the same physical distance on each axis. This gives a more truthful depiction of the relationship between the two variables since the aspect ratio can change the angle of our smoothing line. This would give an erroneous impression of the data. Of course the underlying linear models don't change, but our perception can be influenced by the angle drawn.
A plot using the iris dataset, of sepal width vs. sepal length colored by species, is shown in the viewer.
This exercise is part of the course
Intermediate Data Visualization with ggplot2
Exercise instructions
- Add a fixed coordinate layer to force a 1:1 aspect ratio.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
ggplot(iris, aes(x = Sepal.Length, y = Sepal.Width, color = Species)) +
geom_jitter() +
geom_smooth(method = "lm", se = FALSE) +
# Fix the coordinate ratio
___