def test_point_snapping_break_ties(self):
"""DelineateIt: distance ties are broken using flow accumulation."""
from natcap.invest.delineateit import delineateit
srs = osr.SpatialReference()
srs.ImportFromEPSG(32731) # WGS84/UTM zone 31s
wkt = srs.ExportToWkt()
# need stream layer, points
stream_matrix = numpy.array(
[[0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0], [0, 1, 1, 1, 1, 1], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0]],
dtype=numpy.int8)
stream_raster_path = os.path.join(self.workspace_dir, 'streams.tif')
flow_accum_array = numpy.array(
[[1, 5, 1, 1, 1, 1], [1, 5, 1, 1, 1, 1], [1, 5, 1, 1, 1, 1],
[1, 5, 1, 1, 1, 1], [1, 5, 9, 9, 9, 9], [1, 4, 1, 1, 1, 1],
[1, 4, 1, 1, 1, 1]],
dtype=numpy.int8)
flow_accum_path = os.path.join(self.workspace_dir, 'flow_accum.tif')
pygeoprocessing.numpy_array_to_raster(stream_matrix, 255, (2, -2),
(2, -2), wkt, stream_raster_path)
pygeoprocessing.numpy_array_to_raster(flow_accum_array, -1, (2, -2),
(2, -2), wkt, flow_accum_path)
source_points_path = os.path.join(self.workspace_dir,
'source_features.geojson')
source_features = [Point(9, -7)] # equidistant from two streams
pygeoprocessing.shapely_geometry_to_vector(
source_features,
source_points_path,
wkt,
'GeoJSON',
ogr_geom_type=ogr.wkbUnknown)
snapped_points_path = os.path.join(self.workspace_dir,
'snapped_points.gpkg')
snap_distance = 10 # large enough to get multiple streams per point.
delineateit.snap_points_to_nearest_stream(source_points_path,
stream_raster_path,
flow_accum_path,
snap_distance,
snapped_points_path)
snapped_points_vector = gdal.OpenEx(snapped_points_path,
gdal.OF_VECTOR)
snapped_points_layer = snapped_points_vector.GetLayer()
# should snap to stream point [4, 3] in the array above
# if not considering flow accumulation, it would snap to the
# nearest stream point found first in the array, at [2, 1]
points = [
shapely.wkb.loads(bytes(feature.GetGeometryRef().ExportToWkb()))
for feature in snapped_points_layer
]
self.assertEqual(len(points), 1)
self.assertEqual((points[0].x, points[0].y), (9, -11))
def test_point_snapping_multipoint(self):
"""DelineateIt: test multi-point snapping."""
from natcap.invest.delineateit import delineateit
srs = osr.SpatialReference()
srs.ImportFromEPSG(32731) # WGS84/UTM zone 31s
wkt = srs.ExportToWkt()
# need stream layer, points
stream_matrix = numpy.array(
[[0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0], [0, 1, 1, 1, 1, 1], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0]],
dtype=numpy.int8)
stream_raster_path = os.path.join(self.workspace_dir, 'streams.tif')
# byte datatype
pygeoprocessing.numpy_array_to_raster(stream_matrix, 255, (2, -2),
(2, -2), wkt, stream_raster_path)
source_points_path = os.path.join(self.workspace_dir,
'source_features.gpkg')
gpkg_driver = gdal.GetDriverByName('GPKG')
points_vector = gpkg_driver.Create(source_points_path, 0, 0, 0,
gdal.GDT_Unknown)
layer_name = os.path.splitext(os.path.basename(source_points_path))[0]
points_layer = points_vector.CreateLayer(layer_name,
points_vector.GetSpatialRef(),
ogr.wkbUnknown)
# Create a bunch of points for the various OGR multipoint types and
# make sure that they are all snapped to exactly the same place.
points_layer.StartTransaction()
for multipoint_type in (ogr.wkbMultiPoint, ogr.wkbMultiPointM,
ogr.wkbMultiPointZM, ogr.wkbMultiPoint25D):
new_feature = ogr.Feature(points_layer.GetLayerDefn())
new_geom = ogr.Geometry(multipoint_type)
component_point = ogr.Geometry(ogr.wkbPoint)
component_point.AddPoint(3, -5)
new_geom.AddGeometry(component_point)
new_feature.SetGeometry(new_geom)
points_layer.CreateFeature(new_feature)
# Verify point snapping will run if we give it empty multipoints.
for point_type in (ogr.wkbPoint, ogr.wkbMultiPoint):
new_feature = ogr.Feature(points_layer.GetLayerDefn())
new_geom = ogr.Geometry(point_type)
new_feature.SetGeometry(new_geom)
points_layer.CreateFeature(new_feature)
points_layer.CommitTransaction()
snapped_points_path = os.path.join(self.workspace_dir,
'snapped_points.gpkg')
snap_distance = 10 # large enough to get multiple streams per point.
delineateit.snap_points_to_nearest_stream(source_points_path,
(stream_raster_path, 1),
snap_distance,
snapped_points_path)
try:
snapped_points_vector = gdal.OpenEx(snapped_points_path,
gdal.OF_VECTOR)
snapped_points_layer = snapped_points_vector.GetLayer()
# All 4 multipoints should have been snapped to the same place and
# should all be Point geometries.
self.assertEqual(4, snapped_points_layer.GetFeatureCount())
expected_feature = shapely.geometry.Point(5, -5)
for feature in snapped_points_layer:
shapely_feature = shapely.wkb.loads(
bytes(feature.GetGeometryRef().ExportToWkb()))
self.assertTrue(shapely_feature.equals(expected_feature))
finally:
snapped_points_layer = None
snapped_points_vector = None
def test_point_snapping(self):
"""DelineateIt: test point snapping."""
from natcap.invest.delineateit import delineateit
srs = osr.SpatialReference()
srs.ImportFromEPSG(32731) # WGS84/UTM zone 31s
wkt = srs.ExportToWkt()
# need stream layer, points
stream_matrix = numpy.array(
[[0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0], [0, 1, 1, 1, 1, 1], [0, 1, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0]],
dtype=numpy.int8)
stream_raster_path = os.path.join(self.workspace_dir, 'streams.tif')
# byte datatype
pygeoprocessing.numpy_array_to_raster(stream_matrix, 255, (2, -2),
(2, -2), wkt, stream_raster_path)
source_points_path = os.path.join(self.workspace_dir,
'source_features.geojson')
source_features = [
Point(-1, -1), # off the edge of the stream raster.
Point(3, -5),
Point(7, -9),
Point(13, -5),
MultiPoint([(13, -5)]),
box(-2, -2, -1, -1), # Off the edge
]
fields = {'foo': ogr.OFTInteger, 'bar': ogr.OFTString}
attributes = [
{
'foo': 0,
'bar': '0.1'
},
{
'foo': 1,
'bar': '1.1'
},
{
'foo': 2,
'bar': '2.1'
},
{
'foo': 3,
'bar': '3.1'
},
{
'foo': 3,
'bar': '3.1'
}, # intentional duplicate fields
{
'foo': 4,
'bar': '4.1'
}
]
pygeoprocessing.shapely_geometry_to_vector(
source_features,
source_points_path,
wkt,
'GeoJSON',
fields=fields,
attribute_list=attributes,
ogr_geom_type=ogr.wkbUnknown)
snapped_points_path = os.path.join(self.workspace_dir,
'snapped_points.gpkg')
snap_distance = -1
with self.assertRaises(ValueError) as cm:
delineateit.snap_points_to_nearest_stream(source_points_path,
(stream_raster_path, 1),
snap_distance,
snapped_points_path)
self.assertTrue('must be >= 0' in str(cm.exception))
snap_distance = 10 # large enough to get multiple streams per point.
delineateit.snap_points_to_nearest_stream(source_points_path,
(stream_raster_path, 1),
snap_distance,
snapped_points_path)
snapped_points_vector = gdal.OpenEx(snapped_points_path,
gdal.OF_VECTOR)
snapped_points_layer = snapped_points_vector.GetLayer()
# snapped layer will include 4 valid points and 1 polygon.
self.assertEqual(5, snapped_points_layer.GetFeatureCount())
expected_geometries_and_fields = [
(Point(5, -5), {
'foo': 1,
'bar': '1.1'
}),
(Point(5, -9), {
'foo': 2,
'bar': '2.1'
}),
(Point(13, -11), {
'foo': 3,
'bar': '3.1'
}),
(Point(13, -11), {
'foo': 3,
'bar': '3.1'
}), # Multipoint now point
(box(-2, -2, -1, -1), {
'foo': 4,
'bar': '4.1'
}), # unchanged
]
for feature, (expected_geom,
expected_fields) in zip(snapped_points_layer,
expected_geometries_and_fields):
shapely_feature = shapely.wkb.loads(
bytes(feature.GetGeometryRef().ExportToWkb()))
self.assertTrue(shapely_feature.equals(expected_geom))
self.assertEqual(expected_fields, feature.items())