Create geology layers for a Sequoia project from BRGM data

Uses the project's PARCA layer to download geology datasets and clip them to its geometry.

Usage

seq_geol(
  dirname = ".",
  key = NULL,
  cache = NULL,
  verbose = TRUE,
  overwrite = FALSE
)

Arguments

dirname: character Directory where the matrice file is located. Defaults to the current working directory.
key: character. Optional geology layer identifier(s). If NULL (default), all available geology layers are created. Available layers are "bdcharm50" and "carhab". Partial matching is supported (see seq_key()).
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 invisible named list of file paths to the created layers.

Details

Layers and their associated QML style files are written to the project directory using seq_write().

Difference between BRGM and CARHAB data

The BRGM 1:50000 geological maps are detailed, heterogeneous products created for geological interpretation. They include many finely split geological units and may show inconsistencies between neighbouring map sheets due to varying survey dates, methods, and levels of detail.

CARHAB data are a simplified, harmonised reinterpretation of these maps. Geological formations are recoded into broader lithological classes tailored for ecological modelling. The goal is to provide consistent, comparable, and ecologically relevant information across departments.

More info at infoterre