ddbs_crs: Check CRS of spatial objects or database tables

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

Check CRS of spatial objects or database tables

Description

This is an S3 generic that extracts CRS information from various spatial objects.

Usage

ddbs_crs(x, ...)

## S3 method for class 'duckspatial_df'
ddbs_crs(x, ...)

## S3 method for class 'sf'
ddbs_crs(x, ...)

## S3 method for class 'tbl_duckdb_connection'
ddbs_crs(x, ...)

## S3 method for class 'character'
ddbs_crs(x, conn, ...)

## S3 method for class 'duckdb_connection'
ddbs_crs(x, name, ...)

## S3 method for class 'numeric'
ddbs_crs(x, ...)

## S3 method for class 'crs'
ddbs_crs(x, ...)

## S3 method for class 'data.frame'
ddbs_crs(x, ...)

## Default S3 method:
ddbs_crs(x, ...)

Arguments

x	An object containing spatial data. Can be: duckspatial_df: Lazy spatial data frame (CRS from attributes) sf: sf object (CRS from sf metadata) character: Name of table in database (requires conn)
...	Additional arguments passed to methods
conn	A DuckDB connection (required for character method)
name	Table name (for backward compatibility when first arg is connection)

Value

CRS object from sf package

Examples

## Not run: 
## load packages
library(duckdb)
library(duckspatial)
library(sf)

# Method 1: duckspatial_df objects
nc <- ddbs_open_dataset(system.file("shape/nc.shp", package = "sf"))
ddbs_crs(nc)

# Method 2: sf objects
nc_sf <- st_read(system.file("shape/nc.shp", package = "sf"))
ddbs_crs(nc_sf)

# Method 3: table name in database
conn <- ddbs_create_conn(dbdir = "memory")
ddbs_write_table(conn, nc_sf, "nc_table")
ddbs_crs(conn, "nc_table")
ddbs_stop_conn(conn)

## End(Not run)

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