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Generate point geometries from coordinates

Source: R/ddbs_as_spatial.R
ddbs_as_points.Rd

Converts a data frame with coordinate columns into spatial point geometries.

Usage

ddbs_as_points(
  x,
  coords = c("lon", "lat"),
  crs = "EPSG:4326",
  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.

coords

Character vector of length 2 specifying the names of the longitude and latitude columns (or X and Y coordinates). Defaults to c("lon", "lat").

crs

Character or numeric. The Coordinate Reference System (CRS) of the input coordinates. Can be specified as an EPSG code (e.g., "EPSG:4326" or 4326) or a WKT string. Defaults to "EPSG:4326" (WGS84 longitude/latitude).

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 packages
library(duckspatial)

## create sample data with coordinates
cities_df <- data.frame(
  city = c("Buenos Aires", "Córdoba", "Rosario"),
  lon = c(-58.3816, -64.1811, -60.6393),
  lat = c(-34.6037, -31.4201, -32.9468),
  population = c(3075000, 1391000, 1193605)
)

# option 1: convert data frame to sf object
cities_ddbs <- ddbs_as_points(cities_df)

# specify custom coordinate column names
cities_df2 <- data.frame(
  city = c("Mendoza", "Tucumán"),
  longitude = c(-68.8272, -65.2226),
  latitude = c(-32.8895, -26.8241)
)

ddbs_as_points(cities_df2, coords = c("longitude", "latitude"))


## option 2: convert table in duckdb to spatial table

# create a duckdb connection and write data
conn <- duckspatial::ddbs_create_conn()
DBI::dbWriteTable(conn, "cities_tbl", cities_df, overwrite = TRUE)

# convert to spatial table in database
ddbs_as_points(
    x = "cities_tbl",
    conn = conn,
    name = "cities_spatial",
    overwrite = TRUE
)

# read the spatial table
ddbs_read_table(conn, "cities_spatial")
} # }