Make a Choropleth Map of Discrete Variables with leaflet (03_06)

library(tigris)
library(sf)
library(rmapshaper)
library(tidyverse)
library(readxl)
library(janitor)
library(leaflet)

# ==== States Data =====

us_contiguous <- states() %>% 
  clean_names() %>% 
  mutate(statefp = as.numeric(statefp)) %>% 
  filter(statefp < 60,
         !statefp %in% c(2, 15)) %>% 
  ms_simplify()

us_contiguous <- us_contiguous %>% 
  mutate(region = case_when(region == 1 ~ "Northeast",
                            region == 2 ~ "Midwest",
                            region == 3 ~ "South",
                            region == 4 ~ "West"))

colors_of_regions <- list("Northeast" = "#c03728",
                          "Midwest" = "#919c4c",
                          "West" = "#fd8f24",
                          "South" = "#f5c04a")

# ==== Your Data Viz ==== 

us_contiguous <- us_contiguous %>% 
  add_count(region) %>% 
  mutate(region = fct_reorder(region, n),
         region = fct_rev(region))

order_of_regions <- us_contiguous %>% 
  pull(region) %>% 
  levels()

colors_ordered_by_region <- unlist(colors_of_regions[order_of_regions], use.names = FALSE)

pal_us_regions <- colorFactor(colors_ordered_by_region, us_contiguous$region)

us_contiguous %>% 
  leaflet() %>% 
  addPolygons(weight = 1,
              color = "white",
              fillColor = ~pal_us_regions(region),
              fillOpacity = 1) %>% 
  addLegend(pal = pal_us_regions,
            values = ~region,
            opacity = 1, 
            title = "Region <br>(in size order)")