Conditionally Subdivide Bounding Box into Grid Tiles Based on Geographic Extent

This function checks whether the geographic extent of an sf object's bounding box exceeds a specified threshold in degrees (longitude or latitude). If so, it splits the bounding box into a regular grid of rectangular tiles of approximately tile_size_deg degrees in size. If not, it simply returns the original input.

Usage

conditionally_subdivide_bbox(bbox_sf, degree_threshold = 10, tile_size_deg = 5)

Arguments

bbox_sf

An sf object. Only the bounding box is used for subdivision logic.

degree_threshold

Numeric. Threshold in degrees of lat/lon span at which to trigger subdivision. Default is 10.

tile_size_deg

Numeric. Approximate tile width/height in degrees. Default is 5.

Value

An sf object. Either:

• A grid of tiles (rectangular polygons) if subdivision is triggered, or

• The original input bbox_sf unchanged.

Details

This is useful to improve performance when running spatial operations (e.g., intersect) on large countries or regions by breaking the work into spatial chunks that benefit from spatial indexing.

Examples

if (FALSE) { # \dontrun{
  world <- sf::st_read(system.file("shape/nc.shp", package = "sf"))
  tiles <- conditionally_subdivide_bbox(world)
  plot(st_geometry(world))
  plot(st_geometry(tiles), add = TRUE, border = "red")
} # }