def test_polygonize(self):
"""Test if we can polygonize a raster using GDAL."""
raster_path = standard_data_path(
'hazard', 'classified_flood_20_20.asc')
driver = ogr.GetDriverByName('ESRI Shapefile')
expected_field_name = 'my_field'
shapefile = polygonize(raster_path, 1, expected_field_name)
data_source = driver.Open(shapefile, 0)
layer = data_source.GetLayer()
layer_definition = layer.GetLayerDefn()
field_name = layer_definition.GetFieldDefn(0).GetName()
self.assertEqual(field_name, expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 400)
layer.SetAttributeFilter('%s = 1' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 133)
layer.SetAttributeFilter('%s = 2' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 134)
layer.SetAttributeFilter('%s = 3' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 133)
def test_polygonize(self):
"""Test if we can polygonize a raster using GDAL."""
raster_path = test_data_path('hazard', 'classified_flood_20_20.asc')
driver = ogr.GetDriverByName('ESRI Shapefile')
expected_field_name = 'my_field'
shapefile = polygonize(raster_path, 1, expected_field_name)
data_source = driver.Open(shapefile, 0)
layer = data_source.GetLayer()
layer_definition = layer.GetLayerDefn()
field_name = layer_definition.GetFieldDefn(0).GetName()
self.assertEqual(field_name, expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 400)
layer.SetAttributeFilter('%s = 1' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 133)
layer.SetAttributeFilter('%s = 2' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 134)
layer.SetAttributeFilter('%s = 3' % expected_field_name)
self.assertEquals(layer.GetFeatureCount(), 133)
def reclassify_polygonize(input_raster, ranges, name_field='DN'):
"""Reclassify and polygonize a raster according to some ranges.
.. note:: Delegates to reclassify() and
safe.gis.gdal_ogr_tools.polygonize()
.. versionadded:: 3.4
:param input_raster: The file path to the raster to reclassify.
:type input_raster: str
:param ranges: The ranges as a OrderedDict.
:type ranges: OrderedDict
:param name_field: The name of the field with the cell value.
:type name_field: str
:return: The file path to shapefile.
:rtype: str
"""
return polygonize(reclassify(input_raster, ranges), name_field=name_field)