I want to create a very simple script in python that polygonizes a raster. Based on python cookbook + forums search I wrote the following code
#import des modules from osgeo import gdal, ogr from qgis.core import * from qgis.gui import * import sys from PyQt4.QtCore import * ##srcRaster=Raster ##Result=output vector # 1. Open Raster and get band 1 src_ds = gdal.Open(srcRaster) srcband = src_ds.GetRasterBand(1) # 2. Create output datasource Result = QgsVectorLayer("Polygon", "temporary_points", "memory") Result.startEditing() Result.dataProvider().addAttributes([QgsField("ClassNo", QVariant.String)]) Result.updateFields() gdal.Polygonize( srcband, None, Result, 0, , callback=None )
which ends up with the error "in method 'Polygonize', argument 3 of type 'OGRLayerShadow *". The truth is, I don't really understand what should be the syntax of gdal_polygonize in a qgis python script (command line can be found here).
Could anybody please help ?