Generating compact scientific notation with ggplot2 on R

Question

The plots I generate with ggplot2 look like the one on the left with the full scientific notation on each tick of the y axis. How can I get it to look more compact like the plot on the right, which has the scientific notation labeled in the corner as circled in red?

I have not seen this mentioned in the ggplot2 package documentation or on stack overflow. Does anyone have a workaround?

two formats for scientific notation

Answer 1

Starting with a similar plot:

ggplot(mtcars, aes(wt, mpg * 1E-8)) +
  geom_point()

If we know the scale we want to use, we could define it, and then we could either scale the data on the way in, or change the labels on the y axis, will look the same, except for y axis label (which we could rename whatever we want):

divisor = 1E-8

ggplot(mtcars, aes(wt, mpg * 1E-8 / divisor)) +
  geom_point() +
  labs(title = formatC(divisor, format = "e", digits = 0))

ggplot(mtcars, aes(wt, mpg * 1E-8)) +
  geom_point() +
  scale_y_continuous(labels = function(x) x / divisor) +
  labs(title = formatC(divisor, format = "e", digits = 0))

---

Edit:

If you also want a title, you could alternatively use annotate to write the text outside the plot area, and then scootch the title up:

ggplot(mtcars, aes(wt, mpg * 1E-8)) +
  geom_point() +
  scale_y_continuous(labels = function(x) x / divisor) +
  annotate("text", x = -Inf, y = Inf, hjust = 0, vjust = -0.5,
           label = formatC(divisor, format = "e", digits = 0)) +
  coord_cartesian(clip = "off") +
  labs(title = "Title here") +
  theme(plot.title = element_text(margin = margin(0,0,20,0)))