duckspatial (version 0.9.0)

ddbs_combine: Combine geometries into a single MULTI-geometry

Description

Combines all geometries from a sf object or a DuckDB table into a single MULTI-geometry using the spatial extension. This is equivalent to sf::st_combine(). Returns the result as an sf object or creates a new table in the database.

Usage

ddbs_combine(
  x,
  conn = NULL,
  name = NULL,
  crs = NULL,
  crs_column = "crs_duckspatial",
  overwrite = FALSE,
  quiet = FALSE
)

Value

an sf object or TRUE (invisibly) for table creation

Arguments

x

An sf spatial object. Alternatively, it can be a string with the name of a table with geometry column within the DuckDB database conn. Data is returned from this object.

conn

A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.

name

A character string of length one specifying the name of the table, or a character string of length two specifying the schema and table names. If NULL (the default), the function returns the result as an sf object

crs

The coordinates reference system of the data. Specify if the data doesn't have a crs_column, and you know the CRS.

crs_column

character string specifying the name of the CRS column. Default is "crs_duckspatial"

overwrite

Boolean. whether to overwrite the existing table if it exists. Defaults to FALSE. This argument is ignored when name is NULL.

quiet

A logical value. If TRUE, suppresses any informational messages. Defaults to FALSE.

Examples

if (FALSE) {
# load packages
library(duckspatial)
library(sf)

# create a duckdb database in memory (with spatial extension)
conn <- ddbs_create_conn(dbdir = "memory")

# read data
countries_sf <- st_read(system.file("spatial/countries.geojson", package = "duckspatial"))

# store in duckdb
ddbs_write_vector(conn, countries_sf, "countries")

# combine all geometries into one
ddbs_combine(conn = conn, "countries")

# combine without using a connection
ddbs_combine(countries_sf)

# store result in a new table
ddbs_combine(conn = conn, "countries", name = "countries_combined")
}