gdal-raster-sieve - Remove small raster polygons
NAME SYNOPSIS DESCRIPTION Standard options EXAMPLES Example 1: Remove polygons smaller than 10 pixels from the band 2 of araster. AUTHOR COPYRIGHTNAME
gdal-raster-sieve − Remove small raster polygons
Added in version 3.11.
SYNOPSIS
Usage: gdal raster sieve [OPTIONS] <INPUT> <OUTPUT>
Remove small polygons from a raster dataset.
Positional
arguments:
−i, −−input <INPUT> Input raster
dataset [required]
−o, −−output <OUTPUT> Output raster
dataset (created by algorithm) [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]
−−progress Display progress bar
Options:
−f, −−of, −−format,
−−output−format
<OUTPUT−FORMAT> Output format
−−co, −−creation−option
<KEY>=<VALUE> Creation option [may be repeated]
−−overwrite Whether overwriting existing output
is allowed
−−mask <MASK> Use the first band of the
specified file as a validity mask (all pixels with a value
other than zero will be considered suitable for inclusion in
polygons)
−b, −−band <BAND> Input band
(1−based index)
−s, −−size−threshold
<SIZE−THRESHOLD> Minimum size of polygons to
keep (default: 2)
−c, −−connect−diagonal−pixels
Consider diagonal pixels as connected
Advanced
Options:
−−oo, −−open−option
<KEY>=<VALUE> Open options [may be repeated]
−−if, −−input−format
<INPUT−FORMAT> Input formats [may be
repeated]
DESCRIPTION
gdal raster sieve removes raster polygons smaller than a provided threshold size (in pixels) and replaces them with the pixel value of the largest neighbour polygon.
The input dataset is read as integer data which means that floating point values are rounded to integers. Re−scaling source data may be necessary in some cases (e.g. 32−bit floating point data with min=0 and max=1).
Standard options
−f, −−of, −−format, −−output−format <OUTPUT−FORMAT>
Which output raster format to use. Allowed values may be given by gdal −−formats | grep raster | grep rw | sort
−−co <NAME>=<VALUE>
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.
−−overwrite
Allow program to overwrite existing target file or dataset. Otherwise, by default, gdal errors out if the target file or dataset already exists.
−b, −−band <BAND>
Input band (1−based index)
−s, −−size−threshold <SIZE−THRESHOLD>
Minimum size of polygons to keep (default: 2)
−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.
−−mask <MASK>
Use the first band of the specified file as a validity mask: all pixels in the mask band with a value other than zero will be considered suitable for inclusion in polygons.
EXAMPLES
Example 1: Remove polygons smaller than 10 pixels from the band 2 of araster.
$ gdal raster sieve −b 2 −s 10 input.tif output.tif
AUTHOR
Alessandro Pasotti <[email protected]>
COPYRIGHT
1998-2025