Provided by: python-gdal_2.4.0+dfsg-1ubuntu3_amd64 bug


       gdal_polygonize - Produces a polygon feature layer from a raster.

SYNOPSIS [-8] [-nomask] [-mask filename] raster_file [-b band]
                       [-q] [-f ogr_format] out_file [layer] [fieldname]


       This utility 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 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 already exist,
       defaulting to GML format.

       The utility is based on the GDALPolygonize() function which has additional details on the

           (GDAL >= 1.10) Use 8 connectedness. Default is 4 connectedness.

           Do not use the default validity mask for the input band (such as nodata, or alpha

       -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 default validity mask for the input band (such as
           nodata, or alpha masks) will be used (unless -nomask is specified)

           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 specified, the format is
           guessed from the extension (previously was GML). Use the short format name

           The destination vector file to which the polygons will be written.

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

           The name of the field to create (defaults to 'DN').

           The script runs in quiet mode. The progress monitor is suppressed and routine messages
           are not displayed.


       Frank Warmerdam