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GDAL_POLYGONIZE(1)		     GDAL		    GDAL_POLYGONIZE(1)

NAME
       gdal_polygonize - Produces a polygon feature layer from a raster.

SYNOPSIS
	  gdal_polygonize [--help] [--help-general]
			     [-8] [-o <name>=<value>]... [-nomask]
			     [-mask <filename>]	<raster_file> [-b <band>]
			     [-q] [-f <ogr_format>] [-lco <name>=<value>]...
			     [-overwrite] <out_file> [<layer>] [<fieldname>]

DESCRIPTION
       This  utility creates vector polygons for all connected regions of pix-
       els in the raster sharing a common pixel	value.	Each polygon  is  cre-
       ated  with  an attribute	indicating the pixel value of that polygon.  A
       raster mask may also be provided	to determine which pixels are eligible
       for processing.

       The utility will	create the output vector datasource if it does not al-
       ready exist, otherwise it will try to append to an existing one.

       The utility is based on the :GDALPolygonize() function which has	 addi-
       tional details on the algorithm.

       NOTE:
	  gdal_polygonize  is  a Python	utility, and is	only available if GDAL
	  Python bindings are available.

       --help Show this	help message and exit

       --help-general
	      Gives a brief usage message for the generic GDAL commandline op-
	      tions and	exit.

       -8     Use 8 connectedness. Default is 4	connectedness.

       -nomask
	      Do not use the default validity mask for the input band (such as
	      nodata, or alpha masks).

       -mask <filename>
	      Use the first band of the	specified  file	 as  a	validity  mask
	      (zero  is	invalid, non-zero is valid). If	not specified, the de-
	      fault validity mask for the input	band (such as nodata, or alpha
	      masks) will be used (unless -nomask is specified)

       <raster_file>
	      The source raster	file from which	polygons are derived.

       -b <band>
	      The band on <raster_file>	to build the polygons  from.  Starting
	      with  GDAL 2.2, the value	can also be set	to "mask", to indicate
	      that  the	 mask  band  of	 the  first  band  must	 be  used  (or
	      "mask,band_number" for the mask of a specified band)

       -f <ogr_format>
	      Select  the output format. Starting with GDAL 2.3, if not	speci-
	      fied, the	format is guessed from the extension  (previously  was
	      GML). Use	the short format name

       -o <NAME>=<VALUE>
	      New in version 3.7.

	      Polygonize option. See :GDALPolygonize() documentation.

       -lco <NAME>=<VALUE>
	      New in version 3.7.

	      Layer creation option (format specific)

       -overwrite
	      New in version 3.8.

	      Overwrite	the output layer if it already exists.

       <out_file>
	      The  destination vector file to which the	polygons will be writ-
	      ten.

       <layer>
	      The name of the layer created to hold the	polygon	features.

       <fieldname>
	      The name of the field to create (defaults	to "DN").

       -q     The script runs in quiet mode.  The  progress  monitor  is  sup-
	      pressed and routine messages are not displayed.

AUTHOR
       Frank Warmerdam <warmerdam@pobox.com>

COPYRIGHT
       1998-2025

				 Feb 11, 2025		    GDAL_POLYGONIZE(1)

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