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Within Distance predicate

Source: R/ddbs_predicates.R
ddbs_is_within_distance.Rd

Tests if geometries in x are within a specified distance of y. Returns TRUE if geometries are within the distance.

Usage

ddbs_is_within_distance(
  x,
  y,
  distance = NULL,
  conn = NULL,
  id_x = NULL,
  id_y = NULL,
  sparse = TRUE,
  quiet = FALSE
)

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.

y

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

distance

a numeric value specifying the distance for ST_DWithin. Units correspond to the coordinate system of the geometry (e.g. degrees or meters)

conn

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

id_x

Character; optional name of the column in x whose values will be used to name the list elements. If NULL, integer row numbers of x are used.

id_y

Character; optional name of the column in y whose values will replace the integer indices returned in each element of the list.

sparse

A logical value. If TRUE, it returns a sparse index list. If FALSE, it returns a dense logical matrix.

quiet

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

Value

A list where each element contains indices (or IDs) of geometries in y that touch the corresponding geometry in x. See ddbs_predicate() for details.

Details

This is a convenience wrapper around ddbs_predicate() with predicate = "dwithin".

See also

ddbs_predicate() for other spatial predicates.

Examples


## load packages
library(dplyr)
library(duckspatial)
library(sf)

## read countries data, and rivers
countries_sf <- read_sf(system.file("spatial/countries.geojson", package = "duckspatial"))
countries_filter_sf <- countries_sf |> filter(CNTR_ID %in% c("PT", "ES", "FR", "IT"))

## check countries within 1 degree of distance
ddbs_is_within_distance(countries_filter_sf, countries_sf, 1)
#> ✔ Query successful
#> [[1]]
#> [1]   5  64  73  85 160 177
#> 
#> [[2]]
#>  [1]   5  19  60  64  71  79  85  90  91  96 173 178 206
#> 
#> [[3]]
#>  [1]   3  10  60  85  86  90  96 120 178 204 231 235
#> 
#> [[4]]
#> [1]  64 160
#>