vapour-package: vapour

vapour-packageR Documentation

vapour

Description

A lightweight GDAL API package for R.

Details

Provides low-level access to 'GDAL' functionality for R packages. The aim is to minimize the level of interpretation put on the 'GDAL' facilities, to enable direct use of it for a variety of purposes. 'GDAL' is the 'Geospatial Data Abstraction Library' a translator for raster and vector geospatial data formats that presents a single raster abstract data model and single vector abstract data model to the calling application for all supported formats https://gdal.org/.

Lightweight means we access parts of the GDAL API as near as possible to their native usage. GDAL is not a lightweight library, but provide a very nice abstraction over format details for a very large number of different formats.

Functions for raster and vector sources are included.

vapour_all_drivers list of all available drivers, with type and features
vapour_driver report short name of driver that will be used for a data source
vapour_gdal_version report version of GDAL in use
vapour_srs_wkt produce WKT projection string from various projection string inputs
vapour_vsi_list report contents of VSI sources
vapour_raster_gcp return internal ground control points, if present
vapour_raster_info structural metadata of a source
vapour_read_raster read data direct from a window of a raster band source
vapour_sds_names list individual raster sources in a source containing subdatasets
vapour_warp_raster read data direct from a raster source into a specific window
vapour_driver report name of the driver used for a given source
vapour_geom_name report attribute name of geometry
vapour_geom_summary report simple properties of each feature geometry
vapour_layer_names list names of vector layers in a data source
vapour_layer_info list of data source, driver, layer name/s, fields, feature count, projection
vapour_read_extent read the extent, or bounding box, of geometries in a layer
vapour_read_fields read attributes of features in a layer, the columnar data associated with each geometry
vapour_read_geometry read geometry in binary (blob, WKB) form
vapour_read_geometry_ia read geometry by index, arbitrary
vapour_read_geometry_ij read geometry by sequential index, i to j
vapour_read_geometry_text read geometry in text form, various formats
vapour_read_names read the 'names' of features in a layer, the 'FID'
vapour_read_type read the GDAL types of attributes
vapour_report_fields report internal type of each attribute by name

As far as possible vapour aims to minimize the level of interpretation provided for the functions, so that developers can choose how things are implemented. Functions return raw lists or vectors rather than data frames or classed types.

options

The following options can be set to control global behaviour.

Sys.getenv("vapour.sql.dialect") the current SQL dialect in use

SQL dialect

The SQL dialect can be set to "" (empty string), "OGRSQL", or "SQLITE".

The empty string indicates that the native dialect will be used, see OGRSQL and SQLITE for GDAL, accessed 2022-11-11 and the GDAL_DMD_SUPPORTED_SQL_DIALECTS development documentation (since GDAL 3.6).

Setting "NATIVE" as an alias for "" is quite recent and has not been tested with vapour, similarly no testing has been done with non OGRSQL-native or SQLITE-native drivers yet.

Author(s)

Maintainer: Michael Sumner mdsumner@gmail.com (ORCID)

Other contributors:

  • Simon Wotherspoon (RasterIO configuration for resampling options) [contributor]

  • Mark Padgham (helped get started :)) [contributor]

  • Edzer Pebesma (wrote the field-read handling, adapted here from sf) [contributor]

  • Roger Bivand (wrote configure.ac, adapted here from rgdal) [contributor]

  • Jim Hester (wrote CollectorList.h, copied here from fs package) [contributor, copyright holder]

  • Timothy Keitt (wrote GetPointsInternal copied here from rgdal2 package) [contributor]

  • Jeroen Ooms (tweaked build process, provided Windows build tools) [contributor]

  • Dale Maschette (created the hex logo) [contributor]

  • Joseph Stachelek [contributor]

  • Even Rouault (primary author of the COG format and its use of the GDALwarp app-library, example code used by the warper function here) [contributor]

  • Robert Hijmans (code in terra package used as example/inspiration) [contributor]

  • Dewey Dunnington (wrote the columnar-access mode streaming Arrow support) [contributor]

  • Tomas Kalibera [contributor]

See Also

Useful links:


vapour documentation built on June 22, 2024, 10:01 a.m.