GDAL-VECTOR-CLEAN-COVERAGE(1) GDAL GDAL-VECTOR-CLEAN-COVERAGE(1)
gdal-vector-clean-coverage - Remove gaps and overlaps from a polygon
dataset
Added in version 3.12.
Usage: gdal vector clean-coverage [OPTIONS] <INPUT> <OUTPUT>
Alter polygon boundaries to make shared edges identical, removing gaps and overlaps
Positional arguments:
-i, --input <INPUT> Input vector datasets [required]
-o, --output <OUTPUT> Output vector dataset [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]
-q, --quiet Quiet mode (no progress bar)
Options:
-l, --layer, --input-layer <INPUT-LAYER> Input layer name(s) [may be repeated]
-f, --of, --format, --output-format <OUTPUT-FORMAT> Output format ("GDALG" allowed)
--co, --creation-option <KEY>=<VALUE> Creation option [may be repeated]
--lco, --layer-creation-option <KEY>=<VALUE> Layer creation option [may be repeated]
--overwrite Whether overwriting existing output is allowed
--update Whether to open existing dataset in update mode
--overwrite-layer Whether overwriting existing output is allowed
--append Whether appending to existing layer is allowed
Mutually exclusive with --upsert
--output-layer <OUTPUT-LAYER> Output layer name
--skip-errors Skip errors when writing features
--active-layer <ACTIVE-LAYER> Set active layer (if not specified, all)
--snapping-distance <SNAPPING-DISTANCE> Distance tolerance for snapping nodes
--merge-strategy <MERGE-STRATEGY> Algorithm to assign overlaps to neighboring polygons. MERGE-STRATEGY=longest-border|max-area|min-area|min-index
--maximum-gap-width <MAXIMUM-GAP-WIDTH> Maximum width of a gap to be closed
Advanced Options:
--if, --input-format <INPUT-FORMAT> Input formats [may be repeated]
--oo, --open-option <KEY>=<VALUE> Open options [may be repeated]
--output-oo, --output-open-option <KEY>=<VALUE> Output open options [may be repeated]
--upsert Upsert features (implies 'append')
Mutually exclusive with --append
gdal vector clean-coverage modifies boundaries of a polygonal
dataset, such that gaps and overlaps between features are removed and
shared edges are defined using the same vertices. The resulting
dataset will form a polygonal coverage that can be used with gdal
vector simplify-coverage.
This command can also be used as a step of gdal vector pipeline,
although it requires loading the entire dataset into memory at once.
NOTE:
This command requires a GDAL build against the GEOS library
(version 3.14 or greater).
--maximum-gap-width <MAXIMUM-GAP-WIDTH>
Defines the largest area that should be considered a "gap" and
merged into an adjacent polygon. Gaps will be merged unless a
circle with radius larger than the specified tolerance can be
inscribed within the gap. The default maximum gap width is
zero, meaning that gaps are not closed.
--merge-strategy <MERGE-STRATEGY>
Method by which overlaps or gaps should be added to adjacent
polygons. Options include: - longest-border (default): add
areas to the polygon with which the longest border is shared -
max-area: add areas to the largest adjacent polygon -
min-area: add areas to the smallest adjacent polygon -
min-index: add areas to the adjacent polygon that was read
first
--snapping-distance <SNAPPING-DISTANCE>
Controls the node snapping step, when nearby vertices are
snapped together. By default, an automatic snapping distance
is determined based on an analysis of the input. Set to zero
to turn off all snapping.
--active-layer <ACTIVE-LAYER>
Set the active layer. When it is specified, only the layer
specified by its name will be subject to the processing. Other
layers will be not modified. If this option is not specified,
all layers will be subject to the processing.
-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
--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.
-lco <NAME>=<VALUE>
Layer creation option (format specific)
--overwrite
Allow program to overwrite existing target file or dataset.
Otherwise, by default, gdal errors out if the target file or
dataset already exists.
--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.
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.
Example 1: Create and then simplify a polygonal coverage
$ gdal vector pipeline read ne_10m_admin_0_countries.shp ! \
make-valid ! \
clean-coverage ! \
simplify-coverage --tolerance 1 ! \
write countries.shp
Dan Baston <dbaston@gmail.com>
1998-2026
March 20, 2026 GDAL-VECTOR-CLEAN-COVERAGE(1)
NAME
gdal-vector-clean-coverage - Remove gaps and overlaps from a polygon
dataset
Added in version 3.12.
SYNOPSIS
Usage: gdal vector clean-coverage [OPTIONS] <INPUT> <OUTPUT>
Alter polygon boundaries to make shared edges identical, removing gaps and overlaps
Positional arguments:
-i, --input <INPUT> Input vector datasets [required]
-o, --output <OUTPUT> Output vector dataset [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]
-q, --quiet Quiet mode (no progress bar)
Options:
-l, --layer, --input-layer <INPUT-LAYER> Input layer name(s) [may be repeated]
-f, --of, --format, --output-format <OUTPUT-FORMAT> Output format ("GDALG" allowed)
--co, --creation-option <KEY>=<VALUE> Creation option [may be repeated]
--lco, --layer-creation-option <KEY>=<VALUE> Layer creation option [may be repeated]
--overwrite Whether overwriting existing output is allowed
--update Whether to open existing dataset in update mode
--overwrite-layer Whether overwriting existing output is allowed
--append Whether appending to existing layer is allowed
Mutually exclusive with --upsert
--output-layer <OUTPUT-LAYER> Output layer name
--skip-errors Skip errors when writing features
--active-layer <ACTIVE-LAYER> Set active layer (if not specified, all)
--snapping-distance <SNAPPING-DISTANCE> Distance tolerance for snapping nodes
--merge-strategy <MERGE-STRATEGY> Algorithm to assign overlaps to neighboring polygons. MERGE-STRATEGY=longest-border|max-area|min-area|min-index
--maximum-gap-width <MAXIMUM-GAP-WIDTH> Maximum width of a gap to be closed
Advanced Options:
--if, --input-format <INPUT-FORMAT> Input formats [may be repeated]
--oo, --open-option <KEY>=<VALUE> Open options [may be repeated]
--output-oo, --output-open-option <KEY>=<VALUE> Output open options [may be repeated]
--upsert Upsert features (implies 'append')
Mutually exclusive with --append
DESCRIPTION
gdal vector clean-coverage modifies boundaries of a polygonal
dataset, such that gaps and overlaps between features are removed and
shared edges are defined using the same vertices. The resulting
dataset will form a polygonal coverage that can be used with gdal
vector simplify-coverage.
This command can also be used as a step of gdal vector pipeline,
although it requires loading the entire dataset into memory at once.
NOTE:
This command requires a GDAL build against the GEOS library
(version 3.14 or greater).
Standard options
--maximum-gap-width <MAXIMUM-GAP-WIDTH>
Defines the largest area that should be considered a "gap" and
merged into an adjacent polygon. Gaps will be merged unless a
circle with radius larger than the specified tolerance can be
inscribed within the gap. The default maximum gap width is
zero, meaning that gaps are not closed.
--merge-strategy <MERGE-STRATEGY>
Method by which overlaps or gaps should be added to adjacent
polygons. Options include: - longest-border (default): add
areas to the polygon with which the longest border is shared -
max-area: add areas to the largest adjacent polygon -
min-area: add areas to the smallest adjacent polygon -
min-index: add areas to the adjacent polygon that was read
first
--snapping-distance <SNAPPING-DISTANCE>
Controls the node snapping step, when nearby vertices are
snapped together. By default, an automatic snapping distance
is determined based on an analysis of the input. Set to zero
to turn off all snapping.
--active-layer <ACTIVE-LAYER>
Set the active layer. When it is specified, only the layer
specified by its name will be subject to the processing. Other
layers will be not modified. If this option is not specified,
all layers will be subject to the processing.
-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
--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.
-lco <NAME>=<VALUE>
Layer creation option (format specific)
--overwrite
Allow program to overwrite existing target file or dataset.
Otherwise, by default, gdal errors out if the target file or
dataset already exists.
Advanced 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.
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.
EXAMPLES
Example 1: Create and then simplify a polygonal coverage
$ gdal vector pipeline read ne_10m_admin_0_countries.shp ! \
make-valid ! \
clean-coverage ! \
simplify-coverage --tolerance 1 ! \
write countries.shp
AUTHOR
Dan Baston <dbaston@gmail.com>
COPYRIGHT
1998-2026
March 20, 2026 GDAL-VECTOR-CLEAN-COVERAGE(1)