gdalraster (version 1.11.1)

ogrinfo: Retrieve information about a vector data source

Description

ogrinfo() is a wrapper of the ogrinfo command-line utility (see https://gdal.org/programs/ogrinfo.html). This function lists information about an OGR-supported data source. It is also possible to edit data with SQL statements. Refer to the GDAL documentation at the URL above for a description of command-line arguments that can be passed in cl_arg. Requires GDAL >= 3.7.

Usage

ogrinfo(
  dsn,
  layers = NULL,
  cl_arg = as.character(c("-so", "-nomd")),
  open_options = NULL,
  read_only = TRUE,
  cout = TRUE
)

Value

Invisibly, a character string containing information about the vector dataset, or empty string ("") in case of error.

Arguments

dsn

Character string. Data source name (e.g., filename, database connection string, etc.)

layers

Optional character vector of layer names in the source dataset.

cl_arg

Optional character vector of command-line arguments for the ogrinfo command-line utility in GDAL (see URL above for reference). The default is c("-so", "-nomd") (see Note).

open_options

Optional character vector of dataset open options.

read_only

Logical scalar. TRUE to open the data source read-only (the default), or FALSE to open with write access.

cout

Logical scalar. TRUE to write info to the standard C output stream (the default). FALSE to suppress console output.

See Also

ogr2ogr(), the ogr_manage utilities

Examples

src <- system.file("extdata/ynp_fires_1984_2022.gpkg", package="gdalraster")

# Requires GDAL >= 3.7
if (as.integer(gdal_version()[2]) >= 3070000) {
  # Get the names of the layers in a GeoPackage file.
  ogrinfo(src)

  # Summary of a layer
  ogrinfo(src, "mtbs_perims")

  # JSON format
  args <- c("-json", "-nomd")
  json <- ogrinfo(src, "mtbs_perims", args, cout = FALSE)
  #info <- jsonlite::fromJSON(json)

  # Query an attribute to restrict the output of the features in a layer
  args <- c("-ro", "-nomd", "-where", "ig_year = 2020")
  ogrinfo(src, "mtbs_perims", args)

  # Copy to a temporary in-memory file that is writeable
  src_mem <- paste0("/vsimem/", basename(src))
  vsi_copy_file(src, src_mem)
  print(src_mem)

  # Add a column to a layer
  args <- c("-sql", "ALTER TABLE mtbs_perims ADD burn_bnd_ha float")
  ogrinfo(src_mem, cl_arg = args, read_only = FALSE)

  # Update values of the column with SQL and specify a dialect
  sql <- "UPDATE mtbs_perims SET burn_bnd_ha = (burn_bnd_ac / 2.471)"
  args <- c("-dialect", "sqlite", "-sql", sql)
  ogrinfo(src_mem, cl_arg = args, read_only = FALSE)

  vsi_unlink(src_mem)
}