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GDAL-VECTOR-CLEAN-COVERAGE(1)	      GDAL	   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] [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]
	  --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] [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 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 polygo-
     nal 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).

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.  Conse-
	quently a in-memory temporary dataset will be generated, which may cause
	significant processing time at opening.

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

     --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.
	      [image]  Polygon	dataset  before  cleaning (left), after cleaning
	      with default parameters (center), and after cleaning with  --maxi-
	      mum-gap-width 1 (right)..UNINDENT

     --merge-strategy <MERGE-STRATEGY>
	    Method  by	which overlaps or gaps should be added to adjacent poly-
	    gons. Options include: - longest-border (default): add areas to  the
	    polygon  with which the longest border is shared - max-area: add ar-
	    eas 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
	      [image] Polygon dataset before  cleaning	(left),  after	cleaning
	      with "longest-border" merge strategy (center) and --merge-strategy
	      max-area (right)..UNINDENT

     --output-layer
	    Specifies  the  name of the layer to which features will be written.
	    By default, the names of the output layers will be the same  as  the
	    names of the input layers.

     --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 snap-
	    ping.
	      [image]  Polygon	dataset  before  cleaning (left), after cleaning
	      with default snapping distance (center),	and  a	more  aggressive
	      --snapping-distance  0.2	(right).  Note	the  movement in the up-
	      per-left corner of the polygon on the right..UNINDENT

STANDARD OPTIONS
     --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.

     --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 in-
	    stance, 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  op-
	    tions  supported  for a format can be listed with the --formats com-
	    mand line option but the documentation for the format is the defini-
	    tive 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  sev-
	    eral  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  in-
	    stance,  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 op-
	    tions supported for a format can be listed with the  --formats  com-
	    mand line option but the documentation for the format is the defini-
	    tive  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.

     --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.  Other-
	    wise, by default, gdal errors out if the target file or dataset  al-
	    ready 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 data-
	    bases.

     --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 vec-
	    tor  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 suc-
     cessful execution).

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

				  Jun 05, 2026	   GDAL-VECTOR-CLEAN-COVERAGE(1)

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