Leaflet Zip Code Example

Setup

# load packages
library(tigris) 
library(leaflet) 
library(tidyverse)

# cache zip boundaries that are download via tigris package
options(tigris_use_cache = TRUE)

Load and Clean

Variables Used

• Number of tax returns with total income
• Total income amount

# get zip boundaries that start with 282
char_zips <- zctas(cb = TRUE, starts_with = "282")

# get 2016 zip level income data from irs 
irs <- read_csv("https://www.irs.gov/pub/irs-soi/16zpallnoagi.csv")

# all colnames to lowercase 
colnames(irs) <- tolower(colnames(irs))

# calculate mean income at zip level
irs_sub <- 
  irs %>% 
  select(zipcode,
         n02650,        # Number of returns with total income   
         a02650) %>%    # Total income amount (thousands)
  rename(returns = n02650, 
         income = a02650) %>% 
  # calculate mean income
  mutate(income = income * 1000, 
         mean_income = income/returns) %>% 
  arrange(desc(mean_income)) %>% 
  select(zipcode, mean_income)

Join Data

# join zip boundaries and income data 
char_zips <- geo_join(char_zips, 
                      irs_sub, 
                      by_sp = "GEOID10", 
                      by_df = "zipcode",
                      how = "left")

Setup Data for Mapping

# create color palette 
pal <- colorNumeric(
  palette = "Greens",
  domain = char_zips@data$mean_income)

# create labels for zipcodes
labels <- 
  paste0(
    "Zip Code: ",
    char_zips@data$GEOID10, "<br/>",
    "Mean Income: ",
    scales::dollar(char_zips@data$mean_income)) %>%
  lapply(htmltools::HTML)

Make a Map!

char_zips %>% 
  leaflet %>% 
  # add base map
  addProviderTiles("CartoDB") %>% 
  # add zip codes
  addPolygons(fillColor = ~pal(mean_income),
              weight = 2,
              opacity = 1,
              color = "white",
              dashArray = "3",
              fillOpacity = 0.7,
              highlight = highlightOptions(weight = 2,
                                           color = "#666",
                                           dashArray = "",
                                           fillOpacity = 0.7,
                                           bringToFront = TRUE),
              label = labels) %>%
  # add legend
  addLegend(pal = pal, 
            values = ~mean_income, 
            opacity = 0.7, 
            title = htmltools::HTML("Mean Income <br> 
                                    Tax Returns <br> 
                                    by Zip Code <br>
                                    2016"),
            position = "bottomright")