Administrative boundaries from GADM

Downloads (and caches) Global Administrative Areas (GADM) boundaries as an sf tibble via geodata. Level 0 is the country outline, level 1 provinces / states, and level 2 districts. Use the result as admin in plot_sites() / plot_geo(), as an overview for geo_annotation_inset(), or to clip occurrences with geo_intersection() / geo_raster_mask().

Usage

geo_gadm(
  country = "PNG",
  level = 0,
  path = NULL,
  cache_dir = NULL,
  download = TRUE,
  version = "4.1"
)

Arguments

country: ISO3 code or country name understood by geodata::gadm() (for example "PNG" or "Papua New Guinea").
level: Administrative level: 0 (country), 1 (province), or 2 (district).
path: Optional local GeoPackage / shapefile / RDS previously saved with geo_vector_write(). When set, no download is attempted.
cache_dir: Cache directory. Defaults to tools::R_user_dir("tidymapr", "cache")/gadm.
download: Download when the cache is empty? Set FALSE on CRAN or offline runners.
version: GADM version string passed to geodata (default "4.1").

Value

An sf tibble of multipolygons (class tmr_geo_sf).

Details

GADM data are free for academic and non-commercial use; redistribution of the full database (or derived commercial products) is restricted. See https://gadm.org/license.html. This package never bundles GADM files; each call downloads into a user cache (or reads path) and the download is skipped when download = FALSE (the CRAN / offline default pattern).

References

Global Administrative Areas (GADM). https://gadm.org/

Examples

# Offline: read a previously cached GeoPackage
# png <- geo_gadm("PNG", level = 1, path = "png_adm1.gpkg")
#
# Online (needs geodata + network; skipped on CRAN):
# png <- geo_gadm("PNG", level = 1)
# plot_sites(geo_example_sites("wilhelm"), lon, lat, admin = png)