GDAL-VECTOR-SIMPLIFY(1) GDAL GDAL-VECTOR-SIMPLIFY(1)
gdal-vector-simplify - Simplify geometries of a vector dataset
Added in version 3.12.
Usage: gdal vector simplify [OPTIONS] <INPUT> <OUTPUT> <TOLERANCE>
Simplify geometries of a vector dataset.
Positional arguments:
-i, --input <INPUT> Input vector datasets [required]
-o, --output <OUTPUT> Output vector dataset [required]
--tolerance <TOLERANCE> Distance tolerance for simplification. [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)
--active-geometry <ACTIVE-GEOMETRY> Geometry field name to which to restrict the processing (if not specified, all)
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 simplify simplifies geometries, ensuring that the result
is a valid geometry having the same dimension and number of
components as the input.
The simplification uses a maximum distance difference algorithm
similar to the one used in the Douglas-Peucker algorithm.
This done by the OGRGeometry::SimplifyPreserveTopology() method which
preserves the topology per feature, but not for a whole layer. Thus
gaps or overlaps between geometries that were initially contiguous
may happen. To perform simplification that preserves shared
boundaries between geometries, see gdal vector simplify-coverage.
This command can also be used as a step of gdal vector pipeline.
NOTE:
This command requires a GDAL build against the GEOS library.
-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.
--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.
--active-geometry <ACTIVE-GEOMETRY>
Set the active geometry field from its name. When it is
specified, only the specified geometry field will be subject
to the processing. Other geometry fields will be not modified.
If this option is not specified, all geometry fields will be
subject to the processing. This option can be combined
together with --active-layer.
--tolerance <TOLERANCE>
The specified value of this option is the tolerance used to
merge consecutive points of the output geometry using the
OGRGeometry::SimplifyPreserveTopology() method The unit of the
distance is in georeferenced units of the source layer.
--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.
Example 1: Simplify geometries using a tolerance of one km (assuming the
CRS is in meters)
$ gdal vector simplify --tolerance=1000 in.gpkg out.gpkg --overwrite
Even Rouault <even.rouault@spatialys.com>
1998-2026
March 20, 2026 GDAL-VECTOR-SIMPLIFY(1)
NAME
gdal-vector-simplify - Simplify geometries of a vector dataset
Added in version 3.12.
SYNOPSIS
Usage: gdal vector simplify [OPTIONS] <INPUT> <OUTPUT> <TOLERANCE>
Simplify geometries of a vector dataset.
Positional arguments:
-i, --input <INPUT> Input vector datasets [required]
-o, --output <OUTPUT> Output vector dataset [required]
--tolerance <TOLERANCE> Distance tolerance for simplification. [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)
--active-geometry <ACTIVE-GEOMETRY> Geometry field name to which to restrict the processing (if not specified, all)
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 simplify simplifies geometries, ensuring that the result
is a valid geometry having the same dimension and number of
components as the input.
The simplification uses a maximum distance difference algorithm
similar to the one used in the Douglas-Peucker algorithm.
This done by the OGRGeometry::SimplifyPreserveTopology() method which
preserves the topology per feature, but not for a whole layer. Thus
gaps or overlaps between geometries that were initially contiguous
may happen. To perform simplification that preserves shared
boundaries between geometries, see gdal vector simplify-coverage.
This command can also be used as a step of gdal vector pipeline.
NOTE:
This command requires a GDAL build against the GEOS library.
Standard options
-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.
--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.
--active-geometry <ACTIVE-GEOMETRY>
Set the active geometry field from its name. When it is
specified, only the specified geometry field will be subject
to the processing. Other geometry fields will be not modified.
If this option is not specified, all geometry fields will be
subject to the processing. This option can be combined
together with --active-layer.
--tolerance <TOLERANCE>
The specified value of this option is the tolerance used to
merge consecutive points of the output geometry using the
OGRGeometry::SimplifyPreserveTopology() method The unit of the
distance is in georeferenced units of the source layer.
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.
EXAMPLES
Example 1: Simplify geometries using a tolerance of one km (assuming the
CRS is in meters)
$ gdal vector simplify --tolerance=1000 in.gpkg out.gpkg --overwrite
AUTHOR
Even Rouault <even.rouault@spatialys.com>
COPYRIGHT
1998-2026
March 20, 2026 GDAL-VECTOR-SIMPLIFY(1)