ddbs_remove_repeated_points: Remove repeated points from a geometry

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

Remove repeated points from a geometry

Description

Removes duplicate consecutive vertices from geometries, optionally within a tolerance distance.

Usage

ddbs_remove_repeated_points(
  x,
  tolerance = 0,
  conn = NULL,
  name = 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.
tolerance	A numeric value specifying the minimum distance between consecutive vertices. Vertices closer than this threshold are considered repeated and removed. Default is 0, which removes only exact duplicates.
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
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.

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: 
## load package
library(duckspatial)
library(sf)

## Create a polygon with repeated points
poly <- st_polygon(list(matrix(
  c(0, 0,
    1, 0,
    1, 0,  # repeated point
    1, 1,
    0, 1,
    0, 0),
  ncol = 2, byrow = TRUE
)))

poly_sf <- st_as_sf(st_sfc(poly))

## remove exact duplicate consecutive vertices
ddbs_remove_repeated_points(poly_sf)

## remove vertices within a tolerance of 1 unit
ddbs_remove_repeated_points(poly_sf, tolerance = 1)

## End(Not run)

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