Choroplethr map with midpoint in R

Question

Would someone please help me understand how to format a county level choropleth map in R with a custom color scale? I can't figure out how to get Alaska and Hawaii to update correctly.

I have tried this:

library(choroplethr)
library(ggplot2)
data("df_county_demographics")
df_county_demographics$value<-df_county_demographics$per_capita_income

county_choropleth(df_county_demographics,num_colors = 
1)+scale_fill_gradient2("Score", low = "red", mid = "white",  high = 
"green", midpoint = 20000, na.value = "grey90", label = 
scales::dollar_format())

This updates the continental US how I want it, but not Alaska or Hawaii.

Answer 1

To do this you'll need to use the Object Oriented features of choroplethr. I explain how to do that in the "Advanced Options" section of this part of the choroplethr documentation.