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Computes the maximum inscribed circle of a geometry

Source: R/ddbs_ops_unary.R
ddbs_maximum_inscribed_circle.Rd

Returns the largest circle that fits inside the input geometry. The result is derived from a struct containing the circle's center point, the nearest point on the geometry boundary to that center, and the circle's radius.

Usage

ddbs_maximum_inscribed_circle(
  x,
  geom = "center",
  tolerance = NULL,
  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.

geom

a character string specifying which component of the inscribed circle to return. Must be one of "center" (default) or "nearest". "center" returns the center point of the maximum inscribed circle; "nearest" returns the closest point on the geometry boundary to that center.

tolerance

a numeric value specifying the tolerance used when computing the inscribed circle. If NULL (default), tolerance is computed automatically as max(width, height) / 1000.

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

## return the center point of the maximum inscribed circle
ddbs_maximum_inscribed_circle(argentina_ddbs)

## return the nearest boundary point instead
ddbs_maximum_inscribed_circle(argentina_ddbs, geom = "nearest")

## use a custom tolerance
ddbs_maximum_inscribed_circle(argentina_ddbs, tolerance = 0.01)

## without a connection
ddbs_maximum_inscribed_circle(argentina_ddbs)
} # }