Raster Meets Vector Data - Open Source Geospatial Tools: Applications in Earth Observation - page 127

-q

The script runs in quiet mode. The progress monitor is suppressed and routine
messages are not displayed.
-st threshold
Set the size threshold in pixels. Only raster polygons smaller than this size will
be removed.
-o name=value
Specify a special argument to the algorithm. Currently none are supported.

-4

Four connectedness should be used when determining polygons. That is diagonal
pixels are not considered directly connected. This is the default.

-8

Eight connectedness should be used when determining polygons. That is diagonal
pixels are considered directly connected.
srcfile
The source raster file used to identify target pixels. Only the first band is used.
-nomask
Do not use the default validity mask for the input band (such as no-data, or alpha
masks).
-mask filename
Use the first band of the specified file as a validity mask (zero is invalid, non-zero
is valid).
dstfile
The new file to create with the filtered result. If not provided, the source band is
updated in place.
-of format
Select the output format. The default is GeoTIFF (GTiff). Use the short format
name.

9.2 gdal_polygonize.py

The gdal_polygonize.py Python script converts a raster to a vector file.
Polygons are created for each region where raster cells of the same value are con-
nected. As a default, connectivity is defined in four directions (N-S and W-E). If
the option -8 is set, diagonal (NW-SE, NE-SW) connections are also taken into
account. Pixel values defined as no-data are ignored unless the option -nomask is
set. Likewise, an optional mask image will rule out pixels from the algorithm where
the mask has a zero value.