I've followed instructions in the above mentioned article.
data <- bi_class(stl_race_income, x = pctWhite, y = medInc, style = "quantile", dim = 3)
map <- ggplot() +
geom_sf(data = data, mapping = aes(fill = bi_class), color = "white", size = 0.1, show.legend = FALSE) +
bi_scale_fill(pal = "DkBlue", dim = 3) +
title = "Race and Income in St. Louis, MO",
subtitle = "Dark Blue (DkBlue) Palette"
Above results in: Error in ggplot() : could not find function "ggplot"
How do I fix this? One googled suggestion was to install colorspace, which I did, to no avail.