Execute a lazy query and return the result

Pulls all batches from the execution plan and materializes the result in memory. A plain query returns a data.frame. A query whose output still carries a geometry column, which the spatial verbs (spatial_map(), spatial_join(), spatial_clip(), spatial_overlay() and the rest) mark on the node, returns an sf object, with the hex-WKB column decoded and the node's coordinate reference system set. A string column whose values are hex-encoded WKB is recognised from its content, so a stored geometry column comes back as sf without any spatial verb. The geometry marker follows the column through filter(), select(), rename(), mutate() and joins, and is dropped once the column is.

Usage

collect(x, ...)

# S3 method for class 'vectra_node'
collect(x, sf = TRUE, geom = NULL, crs = NULL, ...)

Arguments

x: A vectra_node object.
...: Ignored.
sf: If TRUE (default), a spatial result is returned as an sf object. FALSE returns the data.frame with the geometry as a hex-WKB string column. Ignored for a non-spatial query.
geom: Name of a hex-WKB geometry column to decode when the node does not already carry one, for instance a column read straight from a .vtr file. NULL (default) uses the geometry column the node carries.
crs: Coordinate reference system for the sf result. NULL (default) uses the one the node carries, or leaves it unknown.

Value

A data.frame, or an sf object for a spatial query.

Details

For a result still larger than RAM, keep it as a node and write it out with write_vtr(), stream it to a vector file with sf::st_write(), or reduce it with collect_chunked().

Examples

f <- tempfile(fileext = ".vtr")
write_vtr(mtcars, f)
result <- tbl(f) |> collect()
head(result)
unlink(f)