DOKK / manpages / debian 12 / pktools / pksieve.1.en
pksieve(1) pksieve(1)

pksieve - program to sieve filter raster image


pksieve
-i input [-s size] -o output [options]

pksieve filters small objects (maximum size defined with the option -s) in a raster by replacing them to the largest neighbor object. In this context, objects are defined as pixels of the same value that are also connected. The connection can be defined in four directions (N-S and W-E: set option -c 4) or eight directions (N-S, W-E and diagonals NW-SE, NE-SW: set option -c 8).

Input image file
raster polygons with sizes smaller than this will be merged into their largest neighbour. No sieve is performed if size = 0
Output image file Output image file
the connectedness: 4 directions or 8 directions
the band to be used from input file
Use the first band of the specified file as a validity mask (zero is invalid, non-zero is valid).
Data type for output image ({Byte / Int16 / UInt16 / UInt32 / Int32 / Float32 / Float64 / CInt16 / CInt32 / CFloat32 / CFloat64}). Empty string: inherit type from input image
Output image format (see also gdal_translate(1)). Empty string: inherit from input image
Creation option for output file. Multiple options can be specified.
colour table in ASCII format having 5 columns: id R G B ALFA (0: transparent, 255: solid)
verbose mode if > 0

merge all patches smaller than 5 pixels into bigger classes, using 8 connectivity (horizontal, vertical and diagonal)

pksieve -i input.tif -c 8 -c 5 -o output.shp

01 December 2022