duckspatial (version 0.9.0)

ddbs_simplify: Simplify geometries

Description

Simplifies geometries from a DuckDB table using the Douglas-Peucker algorithm via the spatial extension. Returns the result as an sf object or creates a new table in the database.

Usage

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

Value

an sf object with simplified geometries 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.

tolerance

Tolerance distance for simplification. Larger values result in more simplified geometries.

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

a character string of length one specifying the column storing the CRS (created automatically by ddbs_write_vector). Set to NULL if absent.

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")

## simplify with tolerance of 0.01
ddbs_simplify("countries", tolerance = 0.01, conn)

## simplify without using a connection
ddbs_simplify(countries_sf, tolerance = 0.01)
}