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Check CRS of spatial objects or database tables

Source: R/ddbs_crs.R
ddbs_crs.Rd

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

if (FALSE) { # \dontrun{
## 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)
} # }