Load and optionally filter a single vector layer

This utility function wraps sf::st_read() to load a vector dataset (e.g., from GPKG, GDB, or SHP). It supports optional filtering by ISO3 country code and/or a spatial filter in WKT format. It automatically selects the first available layer if layer_name is not provided and the file type supports layers.

Utilisation

filter_sf(
  file_path,
  iso3 = NULL,
  iso3_column = NULL,
  layer_name = NULL,
  drop3d = TRUE,
  wkt_filter = NULL,
  file_type = NULL
)

Arguments

file_path: Character. Full file path to the vector dataset.
iso3: Character or NULL. ISO3 country code used for attribute filtering.
iso3_column: Character or NULL. Column in the dataset to match iso3.
layer_name: Character or NULL. Optional. Specific layer name for multi-layer formats.
drop3d: Logical. If TRUE, drops Z and M dimensions from geometries.
wkt_filter: Character or NULL. Optional WKT string used for spatial filtering.
file_type: Character or NULL. File type used to determine if layer name inference is required.

Valeur de retour

An sf object with valid geometry, or NULL on failure.

Exemples

if (FALSE) { # \dontrun{
filter_sf("data/layers.gpkg", iso3 = "KEN", iso3_column = "ISO3")
filter_sf("data/boundary.shp", wkt_filter = "POLYGON((...))")
} # }