GDAL-RASTER-POLYGONIZE(1) GDAL GDAL-RASTER-POLYGONIZE(1)
NAME
gdal-raster-polygonize - Create a polygon feature dataset from a raster
band
Added in version 3.11.
SYNOPSIS
Usage: gdal raster polygonize [OPTIONS]
Create a polygon feature dataset from a raster band.
Positional arguments:
-i, --input Input raster dataset [required]
-o, --output Output vector dataset [required]
Common Options:
-h, --help Display help message and exit
--json-usage Display usage as JSON document and exit
--config = Configuration option [may be repeated]
--progress Display progress bar
Options:
-f, --of, --format, --output-format Output format
--co, --creation-option = Creation option [may be repeated]
--lco, --layer-creation-option = 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 layer is allowed
--append Whether appending to existing layer is allowed
-b, --band Input band (1-based index) (default: 1)
-l, --nln, --layer Layer name (default: polygonize)
--attribute-name Name of the field with the pixel value (default: DN)
-c, --connect-diagonal-pixels Consider diagonal pixels as connected
Advanced Options:
--oo, --open-option = Open options [may be repeated]
--if, --input-format Input formats [may be repeated]
DESCRIPTION
gdal raster polygonize creates vector polygons for all connected
regions of pixels in the raster sharing a common pixel value. Each
polygon is created with an attribute indicating the pixel value of that
polygon. A mask (either explicit, or implicit through nodata value or
band) associated to the selected band can be used to determine the
which pixels should be included in the processing.
The utility can create the output vector datasource if it does not
already exist, otherwise it may append to an existing one.
The utility is based on the :GDALPolygonize() function which has
additional details on the algorithm.
The following options are available:
Standard options
-f, --of, --format, --output-format
Which output vector format to use. Allowed values may be given
by gdal --formats | grep vector | grep rw | sort
--co =
Many formats have one or more optional creation options that can
be used to control particulars about the file created. For
instance, the GeoTIFF driver supports creation options to
control compression, and whether the file should be tiled.
May be repeated.
The 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 Raster drivers format specific documentation for legal
creation options for each format.
-lco =
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.
--update
Whether the output dataset must be opened in update mode.
Implies that it already exists.
--overwrite-layer
Whether overwriting the existing output vector layer is allowed.
--append
Whether appending features to the existing output vector layer
is allowed
-b, --band
Picks a particular band to polygonize. Defaults to band 1.
-l, --nln, --layer
Provides a name for the output vector layer. Defaults to
"polygonize".
--attribute-name
The name of the field to create (defaults to "DN").
-c, --connect-diagonal-pixels
Consider diagonal pixels (pixels at the corners) as connected.
The default behavior is to only consider pixels that are
touching the edges as connected, which is the same as
4-connectivity. When this option is selected, the algorithm will
also consider pixels at the corners as connected, which is the
same as 8-connectivity.
Advanced options
--oo =
Dataset open option (format specific).
May be repeated.
--if
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.
EXAMPLES
Example 1: Create a shapefile with polygons for the connected regions of
band 1 of the input GeoTIFF.
gdal raster polygonize input.tif polygonize.shp
AUTHOR
Even Rouault
COPYRIGHT
1998-2025
May 6, 2025 GDAL-RASTER-POLYGONIZE(1)