Provided by: gdal-bin_3.12.0+dfsg-1_amd64 
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 <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 <NAME>=<VALUE>
Dataset open option (format specific).
May be repeated.
--if <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
1998-2025
Nov 07, 2025 GDAL-VECTOR-SIMPLIFY(1)