Polygons

By default the globe_choropleth function will plot data against an internal database of country polygons. Below use a globe4r dataset to plot the percentage of agricultural land available per country.

data(agriland)

create_globe(height = "100vh") %>% 
  globe_choropleth(
    coords(
      country = country_code,
      altitude = percent,
      cap_color = percent
    ), 
    data = agriland
  ) %>% 
  scale_choropleth_cap_color() %>%  
  scale_choropleth_altitude(0.06, 0.1) 

However one is not limited to use those polygons. The latter are defined by GeoJSON which can easily be obtained in R.

1. First use the raster package to fetch the desired map (shapefile).
2. You are advsied to use rmapshaper to simplify the map as it will make it load much faster in the browser.
3. Finally use geojsonio to convert the file to GeoJSON

All of the packages above are available on CRAN.

Install.

pkgs <- c("raster", "rmapshaper", "geojsonio")
install.packages(pkgs)

# get shapefile
india_sp <- raster::getData('GADM', country = 'INDIA', level = 1)

# optionally reduce its size (strongly recommended)
india_small <- rmapshaper::ms_simplify(india_sp, keep = 0.05) 

# convert to JSON
india_geojson <- geojsonio::geojson_list(india_small)

Now we can build mock data to plot against our mock GeoJON. We can fetch the name of each polygon using the NAME_ + level formula, or NAME_1 in our case, this can be found under properties.

regions <- india_geojson$features %>% 
  purrr::map("properties") %>% 
  purrr::map("NAME_1") %>% 
  unlist()

mock_data <- data.frame(
  NAME_1 = regions,
  value = runif(length(regions), 1, 100)
)

mock_data %>% 
  head() %>% 
  knitr::kable()

NAME_1	value
Andaman and Nicobar	31.231427
Goa	50.636614
Gujarat	75.645629
Haryana	57.568385
Himachal Pradesh	74.398263
Jammu and Kashmir	3.341006

Note that the we also use NAME_1 in our data, this will be used internally to match data to their respective polygons.

create_globe() %>% 
  globe_choropleth(
    data = mock_data,
    coords(
      polygon = NAME_1,
      cap_color = value
    ),
    polygons = india_geojson
  ) %>% 
  globe_pov(19, 77, 1) %>% 
  scale_choropleth_cap_color()