gpkg_table: Lazy Access to Tables by Name

In gpkg: Utilities for the Open Geospatial Consortium 'GeoPackage' Format

Lazy Access to Tables by Name

Description

gpkg_table_pragma(): Get information on a table in a GeoPackage (without returning the whole table).

gpkg_table(): Access a specific table (by name) and get a tbl_SQLiteConnection object referencing that table

gpkg_collect(): Alias for gpkg_table(..., collect=TRUE)

gpkg_tbl(): Alias for gpkg_table(..., collect=FALSE)(default) that always returns a tbl_SQLiteConnection object.

gpkg_rast(): Get a SpatRaster object corresponding to the specified table_name

gpkg_vect(): Get a SpatVector object corresponding to the specified table_name

gpkg_sf(): Get a sf-tibble object corresponding to the specified table_name

Usage

gpkg_table_pragma(x, table_name = NULL, ...)

## Default S3 method:
gpkg_table_pragma(x, table_name = NULL, ...)

gpkg_table(
  x,
  table_name,
  collect = FALSE,
  column_names = "*",
  query_string = FALSE,
  ...
)

## Default S3 method:
gpkg_table(
  x,
  table_name,
  collect = FALSE,
  column_names = "*",
  query_string = FALSE,
  ...
)

gpkg_collect(x, table_name, query_string = FALSE, ...)

gpkg_tbl(x, table_name, ...)

gpkg_rast(x, table_name = NULL, ...)

gpkg_vect(x, table_name, ...)

gpkg_sf(x, table_name, ...)

Arguments

x	A geopackage object or character path to GeoPackage file
table_name	character. One or more table names; for gpkg_table_pragma() if table_name=NULL returns a record for each table. gpkg_table() requires table_name be specified
...	Additional arguments. In gpkg_table() arguments in ... are passed to dplyr::tbl(). For gpkg_table_pragma(), ... arguments are (currently) not used. For gpkg_rast() additional arguments are passed to terra::rast(). For gpkg_vect() additional arguments (such as proxy=TRUE) are passed to terra::vect().
collect	logical. Materialize a data.frame object in memory? Default: FALSE requires 'dbplyr' package. TRUE uses 'RSQLite'.
column_names	character. Used only when collect=TRUE. A character vector of column names to select from table_name.
query_string	logical. Return SQLite query rather than executing it? Default: FALSE

Value

gpkg_table(): A 'dbplyr' object of class tbl_SQLiteConnection

gpkg_collect(): An object of class data.frame

gpkg_tbl(): An object of class tbl_SQLiteConnection

gpkg_rast(): A 'terra' object of class SpatRaster

gpkg_vect(): A 'terra' object of class SpatVector (may not contain geometry columns)

⁠gpkg_sf())⁠: An sf-tibble object of class "sf", "tbl_df". If the table contains no geometry column the result is a "tbl_df".

Examples

tf <- tempfile(fileext = ".gpkg")

r <- terra::rast(system.file("extdata", "dem.tif", package = "gpkg"))

gpkg_write(r,
           destfile = tf,
           RASTER_TABLE = "DEM1",
           FIELD_NAME = "Elevation")

gpkg_write(r,
           destfile = tf,
           append = TRUE,
           RASTER_TABLE = "DEM2",
           FIELD_NAME = "Elevation")

g <- geopackage(tf, connect = TRUE)

# inspect gpkg_contents table
gpkg_table(g, "gpkg_contents")

gpkg_contents(g)

# materialize a data.frame from gpkg_2d_gridded_tile_ancillary
library(dplyr, warn.conflicts = FALSE)

gpkg_table(g, "gpkg_2d_gridded_tile_ancillary") %>% 
  dplyr::filter(tpudt_name == "DEM2") %>% 
  dplyr::select(mean, std_dev) %>% 
  dplyr::collect()

gpkg_disconnect(g)

gpkg documentation built on April 3, 2025, 8:55 p.m.