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Download and read BRGM "BD Charm 50" harmonised geology layers

get_brgm.Rd

Downloads and reads the geology layer (S_FGEOL_*.shp) from BRGM "BD Charm 50" ZIP archives for one or several French departments.

Usage

get_brgm(
  deps,
  key = "carhab",
  cache = NULL,
  verbose = FALSE,
  overwrite = FALSE
)

Arguments

deps

character or numeric; One or sevral french department code (see get_cog()).

key

character Source use to download geology from BRGM. Must be one of:

  • "carhab" : geological data used to created the CarHab dataset ;

  • "bdcharm50" : geological maps, vectorized and harmonised at 1:50,000 scale.

cache

character; Storage directory. Defaults to the user cache directory (see tools::R_user_dir()).

verbose

logical If TRUE, display messages.

overwrite

logical If TRUE, overwrite zipfile.

Value

An sf object containing the geology features for all requested departments.

sf

Details

Multiple departments are combined into a single sf object.

For each department:

  • The corresponding BRGM ZIP archive is obtained via download_brgm() ;

  • The geology shapefile (S_FGEOL_*.shp) is imported ;

  • The layer is read directly from the ZIP using sf::read_sf("/vsizip/...") without extracting files ;

The resulting layers are row-bound into a single sf object. All geometries are returned in the CRS provided by BRGM (typically EPSG:2154).