Materialize a spatial query as an sf object

Collects a vectra_node (typically the result of spatial_map() or spatial_join()) into memory and rebuilds an sf object from its hex-WKB geometry column. The CRS defaults to the one carried on the node.

Usage

collect_sf(x, geom = "geometry", crs = NULL)

Arguments

x

A vectra_node with a hex-WKB / WKT geometry column, or a data.frame already collected from one.

geom

Name of the geometry column. Default "geometry".

crs

Override the coordinate reference system. Defaults to the CRS the node carries, or unknown.

Value

An sf object.

Details

This is the spatial counterpart to collect(): use it when the final result fits in memory as sf. For a result still larger than RAM, keep it as a node and write it out with write_vtr() (the geometry stays as a WKB string column) or reduce it with collect_chunked().

See also

spatial_map(), spatial_join(), collect().

Examples

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
f <- tempfile(fileext = ".vtr")
write_vtr(data.frame(
  NAME = nc$NAME,
  geometry = sf::st_as_binary(sf::st_geometry(nc), hex = TRUE)
), f)
result <- tbl(f) |> spatial_map(~ sf::st_centroid(.x), crs = sf::st_crs(nc))
collect_sf(result)
unlink(f)