.. _vector.flatgeobuf:

FlatGeobuf
==========

.. versionadded:: 3.1

.. shortname:: FlatGeobuf

.. built_in_by_default::

This driver implements read/write support for access to features encoded
in `FlatGeobuf <https://github.com/bjornharrtell/flatgeobuf>`__ format, a
performant binary encoding for geographic data based on flatbuffers that
can hold a collection of Simple Features.

Driver capabilities
-------------------

.. supports_create::

.. supports_georeferencing::

.. supports_virtualio::

Multi layer support
-------------------

A single .fgb file only contains one single layer. For multiple layer support,
it is possible to put several .fgb files in a directory, and use that directory
name as the connection string.

On creation, passing a filename without a .fgb suffix will instruct the driver
to create a directory of that name, and create layers as .fgb files in that
directory.

Starting with GDAL 3.9, metadata set at the layer level will be written in the
FlatGeobuf header, and retrieved on reading as layer metadata.

Open options
------------

|about-open-options|
The following open options are supported:

-  .. oo:: VERIFY_BUFFERS
      :choices: YES, NO
      :default: YES

      Set to YES to verify buffers when reading.
      This can provide some protection for invalid/corrupt data with a performance
      trade off.

Dataset Creation Options
------------------------

None

Layer Creation Options
----------------------

|about-layer-creation-options|
The following layer creation options are supported:

-  .. lco:: SPATIAL_INDEX
      :choices: YES, NO
      :default: YES

      Set to YES to create a spatial index.

-  .. lco:: TEMPORARY_DIR
      :choices: <path>

      Path to an existing directory where temporary
      files should be created. Only used if :lco:`SPATIAL_INDEX=YES`. If not specified,
      the directory of the output file will be used for regular filenames. For
      other VSI file systems, the temporary directory will be the one decided by
      the :cpp:func:`CPLGenerateTempFilename` function.
      "/vsimem/" can be used for in-memory temporary files.

-  .. lco:: TITLE
      :choices: <string>
      :since: 3.9

      Dataset title (should be relatively short)

-  .. lco:: DESCRIPTION
      :choices: <string>
      :since: 3.9

      Dataset description (intended for free form long text)

Creation Issues
---------------

* Currently, NULL geometries are not supported with :lco:`SPATIAL_INDEX=YES`.

  `More background and dicussion on this issue at <https://github.com/flatgeobuf/flatgeobuf/discussions/260>`__

* The creation of the packet Hilbert R-Tree requires an amount of RAM which
  is at least the number of features times 83 bytes.

Examples
--------

-  Simple translation of a single shapefile into a FlatGeobuf file. The file
   'filename.fgb' will be created with the features from abc.shp and attributes
   from abc.dbf. The file ``filename.fgb`` must **not** already exist,
   as it will be created.

   ::

      ogr2ogr -f FlatGeobuf filename.fgb abc.shp

-  Conversion of a Geopackage file with multiple layers:

   ::

      ogr2ogr -f FlatGeobuf my_fgb_dataset input.gpkg

See Also
--------

-  `FlatGeobuf at GitHub <https://github.com/bjornharrtell/flatgeobuf>`__
