Skip to contents

Reduce the coordinate precision of geometries

Source: R/ddbs_ops_unary.R
ddbs_reduce_precision.Rd

Snaps the coordinates of geometries to a regular grid, reducing their precision. Coordinates are rounded to the nearest multiple of precision (e.g. precision = 0.1 keeps one decimal place, precision = 1 snaps to integers). The CRS is preserved.

Usage

ddbs_reduce_precision(
  x,
  precision,
  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.

precision

Numeric grid size to snap coordinates to. Smaller values keep more precision (e.g. 0.001); larger values snap more aggressively (e.g. 1 snaps to integers).

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

if (FALSE) { # \dontrun{
## load package
library(duckspatial)

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

## snap coordinates to a 0.01 grid
ddbs_reduce_precision(countries_ddbs, precision = 0.01)
} # }