urbnmapr

The urbnmapr package provides state and county shapefiles in tibble format that is compatible to map with ggplot2.

Shapefiles include Alaska and Hawaii, transformed to be displayed as insets within the continental United States.

This package is heavily inspired by and derived in part from the fiftystater package by William Murphy. In contrast, urbnmapr:

• Uses shapefiles from the US Census Bureau
• Converts the shapefile data to a tibble dataframe
• Adds various identifiers for merging
• Includes a county-level shapefile

Installation

You can install the latest version of urbnmapr from GitHub:

# install.packages("devtools")
devtools::install_github("UrbanInstitute/urbnmapr")

Usage

Quick maps

urbnmapr contains two tibble dataframes for creating maps:

• states
• counties

The states and counties tibbles can be used with geom_polygon() and coord_map() to create base maps of the continental United States, with Alaska and Hawaii displayed as insets:

library(tidyverse)
library(urbnmapr)

states %>%
  ggplot(aes(long, lat, group = group)) +
  geom_polygon(fill = "grey", color = "#ffffff", size = 0.25) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45)

counties %>%
  ggplot(aes(long, lat, group = group)) +
  geom_polygon(fill = "grey", color = "#ffffff", size = 0.05) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45)

More maps

Additional maps can be accessed with get_urbn_map(). Use the function to create a tibble in your global environment and then map using the same syntax as above.

territories_counties <- get_urbn_map(map = "territories_counties")

territories_counties %>%
  ggplot(aes(long, lat, group = group)) +
  geom_polygon(fill = "grey", color = "#ffffff", size = 0.05) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45)

Labels

Labels for all maps can be accessed with get_urbn_labels(). Use the function to call the appropriate labels and then label the map with geom_text(). Labels can be called inside of geom_text():

states %>%
  ggplot() +
  geom_polygon(aes(long, lat, group = group), 
               fill = "grey", color = "#ffffff", size = 0.25) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45) +
  geom_text(data = get_urbn_labels(map = "states"), aes(x = long, lat, label = state_abbv), 
            size = 3)

Or before geom_text() is called:

territories <- get_urbn_map(map = "territories")
labels <- get_urbn_labels(map = "territories")

territories %>%
  ggplot() +
  geom_polygon(aes(long, lat, group = group),
               fill = "grey", color = "#ffffff", size = 0.05) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45) +
  geom_text(data = labels, aes(x = long, lat, label = state_abbv), size = 3) 

Merging Data

The states and counties tibbles include various identifiers to simplify merging data. The states states tibble contains state_fips, state_abbv, and state_name. The counties tibble contains county_fips, state_abbv, state_fips, county_name, and state_name. Both tibbles can be piped into ggplot2 to create a choropleth map.

statedata %>% 
  left_join(states, by = "state_name") %>% 
  ggplot(mapping = aes(long, lat, group = group, fill = horate)) +
  geom_polygon(color = "#ffffff", size = .25) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45) +
  labs(fill = "Homeownership rate")

household_data <- left_join(countydata, counties, by = "county_fips") 

household_data %>%
  ggplot(aes(long, lat, group = group, fill = medhhincome)) +
    geom_polygon(color = "#ffffff", size = 0.05) +
    coord_map(projection = "albers", lat0 = 39, lat1 = 45)

Styles

library(urbnmapr) works well with the Urban Institute ggplot2 theme.

library(urbnthemes)

set_urbn_defaults(style = "map")

statedata %>% 
  left_join(states, by = "state_name") %>% 
  ggplot(mapping = aes(long, lat, group = group, fill = horate)) +
  geom_polygon(color = "#ffffff", size = .25) +
  coord_map(projection = "albers", lat0 = 39, lat1 = 45) +
  scale_fill_gradientn(labels = scales::percent) +
  labs(fill = "Homeownership rate")

household_data %>%
  filter(state_name %in% c("Virginia", "Maryland", "District of Columbia")) %>%
  ggplot(aes(long, lat, group = group, fill = medhhincome)) +
    geom_polygon(color = "#ffffff", size = 0.05) +
    coord_map(projection = "albers", lat0 = 39, lat1 = 45) +
    scale_fill_gradientn(labels = scales::dollar) +
  labs(fill = "Median household income")

License

Code released under the GNU General Public License v3.0.

Code of conduct

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.