sfarrow (version 0.4.1)

write_sf_dataset: Write sf object to an Arrow multi-file dataset

Description

Write sf object to an Arrow multi-file dataset

Usage

write_sf_dataset(
  obj,
  path,
  format = "parquet",
  partitioning = dplyr::group_vars(obj),
  ...
)

Arguments

obj

object of class sf

path

string path referencing a directory for the output

format

output file format ("parquet" or "feather")

partitioning

character vector of columns in obj for grouping or the dplyr::group_vars

...

additional arguments and options passed to arrow::write_dataset

Value

obj invisibly

Details

Translate an sf spatial object to data.frame with WKB geometry columns and then write to an arrow dataset with partitioning. Allows for dplyr grouped datasets (using group_by) and uses those variables to define partitions.

See Also

write_dataset, st_read_parquet

Examples

# NOT RUN {
# read spatial object
nc <- sf::st_read(system.file("shape/nc.shp", package="sf"), quiet = TRUE)

# create random grouping
nc$group <- sample(1:3, nrow(nc), replace = TRUE)

# use dplyr to group the dataset. %>% also allowed
nc_g <- dplyr::group_by(nc, group)

# write out to parquet datasets
tf <- tempfile()  # create temporary location
on.exit(unlink(tf))
# partitioning determined by dplyr 'group_vars'
write_sf_dataset(nc_g, path = tf)

list.files(tf, recursive = TRUE)

# open parquet files from dataset
ds <- arrow::open_dataset(tf)

# create a query. %>% also allowed
q <- dplyr::filter(ds, group == 1)

# read the dataset (piping syntax also works)
nc_d <- read_sf_dataset(dataset = q)

nc_d
plot(sf::st_geometry(nc_d))

# }