GDAL-VECTOR-CHECK-COVERAGE(1)

NAME
gdal-vector-check-coverage - Check polygon coverage for validity

Added in version 3.12.

SYNOPSIS

            Usage: gdal vector check-coverage [OPTIONS] <INPUT> <OUTPUT>

            Check a polygon coverage for validity

            Positional arguments:
              -i, --input <INPUT>                                  Input vector datasets [required] [not available in pipelines]
              -o, --output <OUTPUT>                                Output vector dataset [required] [not available in pipelines]

            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]
              -q, --quiet                                          Quiet mode (no progress bar or warning message) [not available in pipelines]

            Options:
              -l, --layer, --input-layer <INPUT-LAYER>             Input layer name(s) [may be repeated] [not available in pipelines]
              -f, --of, --format, --output-format <OUTPUT-FORMAT>  Output format ("GDALG" allowed) [not available in pipelines]
              --co, --creation-option <KEY>=<VALUE>                Creation option [may be repeated] [not available in pipelines]
              --lco, --layer-creation-option <KEY>=<VALUE>         Layer creation option [may be repeated] [not available in pipelines]
              --overwrite                                          Whether overwriting existing output dataset is allowed [not available in pipelines]
              --update                                             Whether to open existing dataset in update mode [not available in pipelines]
              --overwrite-layer                                    Whether overwriting existing output layer is allowed [not available in pipelines]
              --append                                             Whether appending to existing layer is allowed [not available in pipelines]
                                                                   Mutually exclusive with --upsert
              --output-layer <OUTPUT-LAYER>                        Output layer name [not available in pipelines]
              --skip-errors                                        Skip errors when writing features [not available in pipelines]
              --no-create-empty-layers                             Avoid creating layers to which no features will be written [not available in pipelines]
              --include-valid                                      Include valid inputs in output, with empty geometry
              --geometry-field <GEOMETRY-FIELD>                    Name of geometry field to check
              --maximum-gap-width <MAXIMUM-GAP-WIDTH>              Maximum width of a gap to be flagged

            Advanced Options:
              --if, --input-format <INPUT-FORMAT>                  Input formats [may be repeated] [not available in pipelines]
              --oo, --open-option <KEY>=<VALUE>                    Open options [may be repeated] [not available in pipelines]
              --output-oo, --output-open-option <KEY>=<VALUE>      Output open options [may be repeated] [not available in pipelines]
              --upsert                                             Upsert features (implies 'append') [not available in pipelines]
                                                                   Mutually exclusive with --append

DESCRIPTION

gdal vector check-coverage checks whether a polygon dataset forms a valid coverage, meaning:

    •   no polygons overlap

    •   all shared edges have nodes at the same locations

    •   any gaps between polygons are larger than a specified width

For each polygon not satisfying these criteria, a linear feature with the geometry of the invalid edge is output. If the coverage is valid, the output dataset will be empty unless --include-valid is used.

It is assumed that the individual polygons are themselves valid according to the OGC Simple Features standard. This can be checked by gdal vector check-geometry.
        [image] Polygon dataset (left) and locations of invalid coverage edges (right)..UNINDENT

    NOTE:
            This command requires a GDAL build against the GEOS library (version 3.12 or greater).

GDALG OUTPUT (ON-THE-FLY / STREAMED DATASET)

This program supports serializing the command line as a JSON file using the GDALG output format. The resulting file can then be opened as a vector dataset using the GDALG: GDAL Streamed Algorithm driver, and apply the specified pipeline in a on-the-fly / streamed way.

NOTE:
        However this algorithm is not natively streaming compatible. Consequently a in-memory temporary dataset will be generated, which may cause significant processing time at opening.

PROGRAM-SPECIFIC OPTIONS

    --geometry-field
        Specify the name of the geometry field to test, for layers having multiple geometry fields. By default the first geometry field will be used.

    --include-valid
        Include features for valid geometries in the output, maintaining 1:1 correspondence between input and output features. The geometry of valid features will be an empty geometry.

    --input-layer
        Specifies the name of the layer to process. By default, all layers will be processed.

    --output-layer
        Specifies the name of the layer to which features will be written. If not specified and there is a single input layer, the name "invalid_edge" will be used. If not specified and there are multiple input layers, features for each input layer will be written to a separate output layer in the format "invalid_edge_{INPUT_LAYER}".

    --maximum-gap-width <MAXIMUM-GAP-WIDTH>
        Defines the largest area that should be considered a gap.

STANDARD OPTIONS

    --append
        Whether appending features to existing layer(s) is allowed. This also creates the output dataset if it does not exist yet.

    --co, --creation-option <NAME>=<VALUE>
        Many formats have one or more optional dataset creation options that can be used to control particulars about the file created. For instance, the GeoPackage driver supports creation options to control the version.

        May be repeated.

        The dataset creation options available vary by format driver, and some simple formats have no creation options at all. A list of options supported for a format can be listed with the --formats command line option but the documentation for the format is the definitive source of information on driver creation options. See Vector drivers format specific documentation for legal creation options for each format.

        Note that dataset creation options are different from layer creation options.

    --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.

    --lco, --layer-creation-option <NAME>=<VALUE>
        Many formats have one or more optional layer creation options that can be used to control particulars about the layer created. For instance, the GeoPackage driver supports layer creation options to control the feature identifier or geometry column name, setting the identifier or description, etc.

        May be repeated.

        The layer creation options available vary by format driver, and some simple formats have no layer creation options at all. A list of options supported for a format can be listed with the --formats command line option but the documentation for the format is the definitive source of information on driver creation options. See Vector drivers format specific documentation for legal creation options for each format.

        Note that layer creation options are different from dataset creation options.

    --no-create-empty-layers
        Added in version 3.13.

        Avoid creating layers to which no features will be written.

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

        May be repeated.

    -f, --of, --format, --output-format <OUTPUT-FORMAT>
        Which output vector format to use. Allowed values may be given by gdal --formats | grep vector | grep rw | sort

    --output-open-option, --output-oo <NAME>=<VALUE>
        Added in version 3.12.

        Dataset open option for output dataset (format specific).

        May be repeated.

    --overwrite
        Allow program to overwrite existing target file or dataset. Otherwise, by default, gdal errors out if the target file or dataset already exists.

    --overwrite-layer
        Whether overwriting the existing output vector layer is allowed.

    --skip-errors
        Added in version 3.12.

        Whether failures to write feature(s) should be ignored. Note that this option sets the size of the transaction unit to one feature at a time, which may cause severe slowdown when inserting into databases.

    --update
        Whether to open an existing output dataset in update mode.

    --upsert
        Added in version 3.12.

        Variant of --append where the OGRLayer::UpsertFeature() operation is used to insert or update features instead of appending with OGRLayer::CreateFeature().

        This is currently implemented only in a few drivers: GPKG -- GeoPackage vector, Elasticsearch: Geographically Encoded Objects for Elasticsearch and MongoDBv3 (drivers that implement upsert expose the GDAL_DCAP_UPSERT capability).

        The upsert operation uses the FID of the input feature, when it is set (and the FID column name is not the empty string), as the key to update existing features. It is crucial to make sure that the FID in the source and target layers are consistent.

        For the GPKG driver, it is also possible to upsert features whose FID is unset or non-significant (the --unset-fid option of gdal vector edit can be used to ignore the FID from the source feature), when there is a UNIQUE column that is not the integer primary key.

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: Output coverage errors in a TopoJSON file to a GeoJSON file

            $ gdal vector check-coverage "https://cdn.jsdelivr.net/npm/us-atlas@3/counties-albers-10m.json" --layer counties counties-errors.geojson

  Example 2: Output invalid coverage features to the command-line as part of a pipeline
Bash

            gdal vector pipeline \
                ! read "https://cdn.jsdelivr.net/npm/us-atlas@3/counties-albers-10m.json" --layer counties \
                ! check-coverage \
                ! info --features
PowerShell

            gdal vector pipeline `
                ! read "https://cdn.jsdelivr.net/npm/us-atlas@3/counties-albers-10m.json" --layer counties `
                ! check-coverage `
                ! info --features

AUTHOR
Dan Baston <dbaston@gmail.com>

COPYRIGHT
1998-2026