plot_usmap Incorrect Legend Values

Question

I am trying to use plot_usmap to map a data frame with two columns - fips and change2 - where the values for change2 range from -34.7 to 91.5. When I run this code:

plot_usmap(regions = "counties", values = "change2", data = map, color = "white") + 
  scale_fill_gradient2(
    low = "red", mid = "grey", high = "dark green", name = "Change from SPLY", label = scales::percent) + 
  theme(legend.position = "right")

The legend gives the values as -3000 to +9000.

Why doesn't the legend match the values of change2? Is there a fix to this that I'm missing?

Answer 1

In case someone else happens to have this issue too, the answer is very obvious:

ggplot multiplies the values by 100 when label = scales::percent, so if your values have already been converted into percentages, then you will get percent*100.