GDAL-VECTOR-EXPORT-SCHEMA(1)

NAME
gdal-vector-export-schema - Export the OGR_SCHEMA from a vector dataset

Added in version 3.13.

SYNOPSIS

    Usage: gdal vector export-schema [OPTIONS] <INPUT>...
    Export the OGR_SCHEMA from a vector dataset.
    Positional arguments:
      -i, --dataset, --input <INPUT>            Input vector datasets [may be repeated] [required]
    Common Options:
      -h, --help                                Display help message and exit
      --json-usage                              Display usage as JSON document and exit
      --config <KEY>=<VALUE>                    Configuration option [may be repeated]
    Options:
      -l, --layer, --input-layer <INPUT-LAYER>  Input layer name [may be repeated]
    Advanced Options:
      --oo, --open-option <KEY>=<VALUE>         Open options [may be repeated]
      --if, --input-format <INPUT-FORMAT>       Input formats [may be repeated]

DESCRIPTION

gdal vector export-schema exports the OGR_SCHEMA from a GDAL-supported vector dataset, and returns it on the standard output stream when used from the command line, or in the output parameter when used from the API.

OGR_SCHEMA is a JSON object describing the structure of a vector dataset according to the schema definition at ogr_fields_override.schema.json

gdal vector export-schema can be used as the last step of a pipeline.

The following options are available:

PROGRAM-SPECIFIC OPTIONS

-l, --layer, --input-layer <INPUT-LAYER>
    Name of one or more layers to inspect. If no layer names are passed, then all layers will be selected.

STANDARD OPTIONS

--oo, --open-option <NAME>=<VALUE>
    Dataset open option (format specific).

    May be repeated.

--if, --input-format <format>
    Format/driver name to be attempted to open the input file(s). It is generally not necessary to specify it, but it can be used to skip automatic driver detection, when it fails to select the appropriate driver. This option can be repeated several times to specify several candidate drivers. Note that it does not force those drivers to open the dataset. In particular, some drivers have requirements on file extensions.

    May be repeated.

RETURN STATUS CODE

The program returns status code 0 in case of success, and non-zero in case of error (non-blocking errors emitted as warnings are considered as a successful execution).

EXAMPLES

  Example 1: Extracting the OGR_SCHEMA from the file poly.gpkg

    gdal vector export-schema poly.gpkg

  Example 2: Save the OGR_SCHEMA to a file

When using Windows PowerShell 5.1, redirecting output with > or Out-File -Encoding utf8 produces UTF-8 with a BOM (Byte Order Mark). When using the schema with gdal vector create it may fail with ERROR 1: JSON parsing error: unexpected character (at offset 0).

In PowerShell 5.1, use -Encoding ascii for JSON output that contains no non-ASCII characters. Bash

    gdal vector export-schema natural_earth_vector.gpkg --layer "ne_50m_admin_0_countries" > countries.json
PowerShell

    # PowerShell 5.1
    gdal vector export-schema natural_earth_vector.gpkg --layer "ne_50m_admin_0_countries" | Out-File countries.json -Encoding ascii
    # PowerShell 7+
    gdal vector export-schema natural_earth_vector.gpkg --layer "ne_50m_admin_0_countries" | Out-File countries.json -Encoding utf8

  Example 3: Validate an OGR_SCHEMA file using Python

Validate against the latest version of the schema definition at ogr_fields_override.schema.json using the Python package check-jsonschema available on PyPI.

    $ pip install check-jsonschema
    $ check-jsonschema --schemafile https://raw.githubusercontent.com/OSGeo/gdal/master/ogr/data/ogr_fields_override.schema.json countries.json --verbose

  Example 4: Create an OGR_SCHEMA at the end of a pipeline

This example renames the field pop_est to estimated_population and changes its type from Real to Integer, before exporting the resulting OGR_SCHEMA. Bash

    gdal vector pipeline \
        ! read natural_earth_vector.gpkg --layer ne_50m_admin_0_countries \
        ! sql --sql "SELECT geom,name,abbrev,pop_est AS estimated_population FROM ne_50m_admin_0_countries" --output-layer "countries" \
        ! set-field-type --field-name "estimated_population" --field-type Integer \
        ! export-schema
PowerShell

    gdal vector pipeline `
        ! read natural_earth_vector.gpkg --layer ne_50m_admin_0_countries `
        ! sql --sql "SELECT geom,name,abbrev,pop_est AS estimated_population FROM ne_50m_admin_0_countries" --output-layer "countries" `
        ! set-field-type --field-name "estimated_population" --field-type Integer `
        ! export-schema

AUTHOR
Alessandro Pasotti <elpaso@itopen.it>

COPYRIGHT
1998-2026