ddbs_filter: Perform a spatial filter

In duckspatial: R Interface to 'DuckDB' Database with Spatial Extension

Perform a spatial filter

Description

Filters geometries based on a spatial relationship with another geometry, such as intersection, containment, or proximity.

Usage

ddbs_filter(
  x,
  y,
  predicate = "intersects",
  conn = NULL,
  conn_x = NULL,
  conn_y = NULL,
  name = NULL,
  distance = NULL,
  mode = NULL,
  overwrite = FALSE,
  quiet = FALSE
)

Arguments

x	Input spatial data. Can be: A duckspatial_df object (lazy spatial data frame via dbplyr) An sf object A tbl_lazy from dbplyr A character string naming a table/view in conn Data is returned from this object.
y	Input spatial data. Can be: A duckspatial_df object (lazy spatial data frame via dbplyr) An sf object A tbl_lazy from dbplyr A character string naming a table/view in conn
predicate	A geometry predicate function. Defaults to intersects, a wrapper of ST_Intersects. See details for other options.
conn	A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.
conn_x	A DBIConnection object to a DuckDB database for the input x. If NULL (default), it is resolved from conn or extracted from x.
conn_y	A DBIConnection object to a DuckDB database for the input y. If NULL (default), it is resolved from conn or extracted from y.
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
distance	a numeric value specifying the distance for ST_DWithin. The units should be specified in meters
mode	Character. Controls the return type. Options: "duckspatial" (default): Lazy spatial data frame backed by dbplyr/DuckDB "sf": Eagerly collected sf object (uses memory) Can be set globally via ddbs_options(mode = "...") or per-function via this argument. Per-function overrides global setting.
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.

Details

Spatial Join Predicates:

A spatial predicate is really just a function that evaluates some spatial relation between two geometries and returns true or false, e.g., “does a contain b” or “is a within distance x of b”. Here is a quick overview of the most commonly used ones, taking two geometries a and b:

• "ST_Intersects": Whether a intersects b

• "ST_Contains": Whether a contains b

• "ST_ContainsProperly": Whether a contains b without b touching a's boundary

• "ST_Within": Whether a is within b

• "ST_Overlaps": Whether a overlaps b

• "ST_Touches": Whether a touches b

• "ST_Equals": Whether a is equal to b

• "ST_Crosses": Whether a crosses b

• "ST_Covers": Whether a covers b

• "ST_CoveredBy": Whether a is covered by b

• "ST_DWithin": x) Whether a is within distance x of b

Value

Depends on the mode argument (or global preference set by ddbs_options):

• duckspatial (default): A duckspatial_df (lazy spatial data frame) backed by dbplyr/DuckDB.

• sf: An eagerly collected object in R memory, that will return the same data type as the sf equivalent (e.g. sf or units vector).

When name is provided, the result is also written as a table or view in DuckDB and the function returns TRUE (invisibly).

Examples

## Not run: 
# RECOMMENDED: Efficient lazy workflow using ddbs_open_dataset
library(duckspatial)

# Load data directly as lazy spatial data frames (CRS auto-detected)
countries <- ddbs_open_dataset(
  system.file("spatial/countries.geojson", package = "duckspatial")
)

argentina <- ddbs_open_dataset(
  system.file("spatial/argentina.geojson", package = "duckspatial")
)

# Lazy filter - computation stays in DuckDB
neighbors <- ddbs_filter(countries, argentina, predicate = "touches")

# Collect to sf when needed
neighbors_sf <- dplyr::collect(neighbors) |> sf::st_as_sf()


# Alternative: using sf objects directly (legacy compatibility)
library(sf)

countries_sf <- st_read(system.file("spatial/countries.geojson", package = "duckspatial"))
argentina_sf <- st_read(system.file("spatial/argentina.geojson", package = "duckspatial"))

result <- ddbs_filter(countries_sf, argentina_sf, predicate = "touches")


# Alternative: using table names in a duckdb connection
conn <- ddbs_create_conn(dbdir = "memory")

ddbs_write_table(conn, countries_sf, "countries")
ddbs_write_table(conn, argentina_sf, "argentina")

ddbs_filter(conn = conn, "countries", "argentina", predicate = "touches")

## End(Not run)

duckspatial documentation built on June 22, 2026, 9:08 a.m.