diff --git a/gdal_boots/gdal.py b/gdal_boots/gdal.py
index c025f41..4ba2dac 100644
--- a/gdal_boots/gdal.py
+++ b/gdal_boots/gdal.py
@@ -616,7 +616,7 @@ def to_vector(self, field_id=-1, callback: Callable[[float, str, Any], None] = N
 
         """
         vds = VectorDataset.create()
-        vds.add_layer("test", VectorDataset.GeometryType.Polygon, self.geoinfo.epsg)
+        vds.add_layer("test", GeometryType.Polygon, self.geoinfo.epsg)
         band = self.ds.GetRasterBand(1)
         gdal.Polygonize(band, band, vds.layers.first().ref_layer, field_id, [], callback=callback)
         vds.ds.FlushCache()
@@ -1174,6 +1174,8 @@ def size(self):
 class VectorDataset:
     # https://livebook.manning.com/book/geoprocessing-with-python/chapter-3/1
 
+    GeometryType = GeometryType
+
     def __init__(self, ds):
         self.ds: ogr.DataSource | gdal.Dataset = ds
         # self.layers = None