I am desperately trying to vectorize raster files in a loop for which I came across GDAL's polygonize function (https://gdal.org/programs/gdal_polygonize.html).

However, I don't get the hang of it. To me, the input parameters are cryptic and I failed to figure out the exact commands required for application in Python.

** Edit**

With help of Ben's comment I got to this point:

from osgeo import gdal, ogr
import sys

# this allows GDAL to throw Python Exceptions
gdal.UseExceptions()

#  get raster datasource
src_ds = gdal.Open(inputFilename)
srcband = src_ds.GetRasterBand(1)

#  create output datasource
dst_layername = "POLYGONIZED_STUFF"
drv = ogr.GetDriverByName("ESRI Shapefile")
dst_ds = drv.CreateDataSource( outputPath+outputFile )
dst_layer = dst_ds.CreateLayer(dst_layername, srs = None )

gdal.Polygonize( srcband, None, dst_layer, -1, [], callback=None )

GDAL now creates three files:

• filename.dbf (6,451 KB)
• filename.shp (75,929 KB)
• filename.shx (1 KB)

However, when I import the file with GeoPandas (test = gpd.read_file(outputPath+outputFile)), the GeoDataFrame is empty.

I am desperately trying to vectorize raster files in a loop for which I came across GDAL's polygonize function (https://gdal.org/programs/gdal_polygonize.html).

However, I don't get the hang of it. To me, the input parameters are cryptic and I failed to figure out the exact commands required for application in Python.

** Edit**

With help of Ben's comment I got to this point:

from osgeo import gdal, ogr
import sys

# this allows GDAL to throw Python Exceptions
gdal.UseExceptions()

#  get raster datasource
src_ds = gdal.Open(inputFilename)
srcband = src_ds.GetRasterBand(1)

#  create output datasource
dst_layername = "POLYGONIZED_STUFF"
drv = ogr.GetDriverByName("ESRI Shapefile")
dst_ds = drv.CreateDataSource( outputPath+outputFile )
dst_layer = dst_ds.CreateLayer(dst_layername, srs = None )

gdal.Polygonize( srcband, None, dst_layer, -1, [], callback=None )

GDAL now creates three files:

• filename.dbf (6,451 KB)
• filename.shp (75,929 KB)
• filename.shx (1 KB)

However, when I import the file with GeoPandas (test = gpd.read_file(outputPath+outputFile)), the GeoDataFrame is empty.

Bzw. I am working with this data set: http://www.earthstat.org/harvested-area-yield-175-crops/

I am desperately trying to vectorize raster files in a loop for which I came across GDAL's polygonize function (https://gdal.org/programs/gdal_polygonize.html).

However, I don't get the hang of it. To me, the input parameters are cryptic and I failed to figure out the exact commands required for application in Python.

In theory, in should be something like this:

import rioxarray
from osgeo import gdal

inputRaster = rioxarray.open_rasterio('file.tif')

gdal.Polygonize(
    inputRaster,
    'outputVector.shp'
    )

But of course this is too simple and does not work.

My raster files has only one band:

cropRaster.shape
Out[18]: (1, 2160, 4320)

What would be the most simpel/straightforward application of GDAL polygonize in Python?

I am desperately trying to vectorize raster files in a loop for which I came across GDAL's polygonize function (https://gdal.org/programs/gdal_polygonize.html).

However, I don't get the hang of it. To me, the input parameters are cryptic and I failed to figure out the exact commands required for application in Python.

** Edit**

With help of Ben's comment I got to this point:

from osgeo import gdal, ogr
import sys

# this allows GDAL to throw Python Exceptions
gdal.UseExceptions()

#  get raster datasource
src_ds = gdal.Open(inputFilename)
srcband = src_ds.GetRasterBand(1)

#  create output datasource
dst_layername = "POLYGONIZED_STUFF"
drv = ogr.GetDriverByName("ESRI Shapefile")
dst_ds = drv.CreateDataSource( outputPath+outputFile )
dst_layer = dst_ds.CreateLayer(dst_layername, srs = None )

gdal.Polygonize( srcband, None, dst_layer, -1, [], callback=None )

GDAL now creates three files:

• filename.dbf (6,451 KB)
• filename.shp (75,929 KB)
• filename.shx (1 KB)

However, when I import the file with GeoPandas (test = gpd.read_file(outputPath+outputFile)), the GeoDataFrame is empty.