README.md

In jjchern/usmapdata: US Map Data from Census

About

Making maps with R has been quite easy due to various packages. For example, the maps package has a function that directly plots US counties:

library(maps)
map("county")

Or use the above data but plot it with ggplot2:

library(ggplot2)
map_data("county") -> map_data_county
ggplot() +
  geom_map(data = map_data_county, map = map_data_county,
           aes(x = long, y = lat, map_id = region),
           color="black", fill="white", size=0.1)

Or with ggcounty:

# devtools::install_github("hrbrmstr/ggcounty")
library(ggcounty)
ggcounty.us() -> us
us$gg

The problem with these maps, however, is that Alaska and Hawaii are often missing. Moving these two states into a US map involves rotating, shrinking, and shifting the corresponding spatial polygons.

The usmapdata package intends to solve this problem by providing tidy data frames that have Alaska and Hawaii in proper place, following the procedure documented nicely in a blog post by Bob Rudis.

Installation

# install.packages("devtools")
devtools::install_github("jjchern/usmapdata")

Usage

Plain County Map

Aftering installing the package, one can get, say, the US county data with usmapdata::county. For example, the following chuck of code plots a county map with ggplot2:

library(ggplot2)
ggplot() +
  geom_map(data = usmapdata::county, map = usmapdata::county,
           aes(x = long, y = lat, map_id = id),
           color="black", fill="white", size=0.1) +
  coord_map("albers", lat0 = 30, lat1 = 40) +
  ggthemes::theme_map()

Plain state Map

library(ggplot2)
ggplot() +
  geom_map(data = usmapdata::state, map = usmapdata::state,
           aes(x = long, y = lat, map_id = id),
           color="black", fill="white", size=0.1) +
  coord_map("albers", lat0 = 30, lat1 = 40) +
  ggthemes::theme_map()

jjchern/usmapdata documentation built on May 19, 2019, 11:39 a.m.