def prepare_strokes_lvl2(delimited_stroke_class):
"""Constructs delimited strokes of level 2 for road sections in strokes that could not be matched."""
not_matched_strokes = session.query(delimited_stroke_class).filter(
delimited_stroke_class.match_id == None)
if delimited_stroke_class == DelimitedStrokeRef:
delimited_strokes = delimited_strokes_ref
else:
delimited_strokes = delimited_strokes_target
for delimited_stroke in not_matched_strokes:
for road_section in delimited_strokes[delimited_stroke.id]:
road_section.delimited_stroke = None
begin_junction = delimited_stroke.begin_junction
for road_section in delimited_strokes[delimited_stroke.id]:
if road_section.delimited_stroke is None:
new_stroke = construct_stroke_from_section(
road_section,
delimited_stroke_class,
level=2,
begin_junction=begin_junction)
extended_stroke = construct_stroke(road_section,
begin_junction,
new_stroke,
level=2)
begin_junction = extended_stroke.end_junction
session.query(delimited_stroke_class).filter(
delimited_stroke_class.level == 1,
delimited_stroke_class.match_id == None).delete()
def get_area(geom):
"""Calculates the area (in m2) of a plane."""
numpoints = session.query(func.st_numpoints(geom))[0][0]
if numpoints > 2:
return session.query(
func.st_area(
func.st_makepolygon(
func.st_addpoint(geom, func.st_startpoint(geom)))))[0][0]
else:
return 0
def angle_at_junction(road_section, junction):
"""Calculates the angle of the line segment of road_section at junction."""
assert (road_section.begin_junction == junction
or road_section.end_junction == junction)
first_point_section = session.query(func.st_startpoint(
road_section.geom))[0][0]
if session.query(func.st_equals(first_point_section, junction.geom))[0][0]:
angle = session.query(
func.ST_Azimuth(junction.geom,
road_section.geom.ST_PointN(2)))[0][0]
else:
angle = session.query(
func.ST_Azimuth(junction.geom,
road_section.geom.ST_PointN(-2)))[0][0]
assert angle is not None
return angle
def preprocess_target(preprocessing_check):
""""Handles the preprocessing of the target dataset. Includes classification of junctions and construction of
delimited strokes at level 1. Set the input preprocessing_check to false if the junctions are already
classified and saved in the database"""
session.query(DelimitedStrokeTarget).delete()
reset_delimited_strokes(session.query(RoadSectionTarget))
junctions_target = session.query(JunctionTarget)
if preprocessing_check:
print("Classifying junctions of the target database.")
classify_junctions(junctions_target)
print("Constructing strokes of the target database.")
construct_strokes(junctions_target, DelimitedStrokeTarget)
remaining_sections_target = session.query(RoadSectionTarget).filter(
RoadSectionTarget.delimited_stroke_id == None)
for road_section in remaining_sections_target:
construct_stroke_from_section(road_section, DelimitedStrokeTarget)
def generate_output(matches):
session.query(LinkingTable).delete()
for match in matches:
strokes = session.query(DelimitedStrokeRef).filter(
DelimitedStrokeRef.match_id == match.id)
if not strokes.first():
# print('Match', match.id, 'no longer exists')
continue
for stroke_ref in match.strokes_ref:
try:
for section_ref in delimited_strokes_ref[stroke_ref.id]:
for stroke_target in match.strokes_target:
for section_target in delimited_strokes_target[
stroke_target.id]:
link = LinkingTable(
nwb_id=section_ref.id,
top10nl_id=section_target.id,
match_id=match.id,
similarity_score=match.similarity_score)
session.add(link)
session.flush()
except KeyError:
print('Stroke', stroke_ref.id,
'not recorded in delimited strokes dictionary')
def set_similarity_score(self):
"""Calculates the similarity score of the match. It is a weighted sum of scaled attributes, which are
difference in length, difference in distance (hausdorff distance) and difference in area."""
length_diff = length_difference(self.strokes_ref, self.strokes_target)
hausdorff = session.query(
func.st_hausdorffdistance(self.geom_ref, self.geom_target))[0][0]
area_diff = self.set_area_difference()
area_diff_normalized = area_diff / get_length(self.strokes_ref)
weights = [0.5, 0.35, 0.15] # sum equal to 1
metrics = [
length_diff / tolerance_length, hausdorff / tolerance_hausdorff,
area_diff_normalized / tolerance_area_normalized
]
score = 0
for index, metric in enumerate(metrics):
score += weights[index] * (1 - metric)
return score
def matching_process(level, tolerance_distance):
"""Searches for a match for each delimited stroke in the reference database."""
strokes_ref = session.query(DelimitedStrokeRef).filter(
DelimitedStrokeRef.level == level, DelimitedStrokeRef.match_id == None)
count = 0
all_matches = []
for stroke in strokes_ref:
try:
matches = find_matching_candidates(stroke, tolerance_distance)
except AssertionError as e:
print(e)
print(traceback.format_exc())
print('Something went wrong trying to find a match for stroke',
stroke.id)
matches = None
# TODO add correct Exception, merging looping road sections is not possible
if matches:
best_score = 0
best_match = None
for match in matches:
if match.similarity_score >= best_score:
best_match = match
best_score = match.similarity_score
if best_match:
for stroke_ref in best_match.strokes_ref:
stroke_ref.match_id = best_match.id
for stroke_target in best_match.strokes_target:
stroke_target.match_id = best_match.id
all_matches.append(best_match)
count += 1
if count % 100 == 0:
print('Strokes analyzed:', count)
return all_matches
def combine_geom(list_of_strokes):
"""Expects a list of strokes, returns a combined geometry of the strokes in the list."""
geoms = [stroke.geom for stroke in list_of_strokes]
return session.query(
func.st_astext(func.st_linemerge(func.st_collect(array(geoms)))))[0][0]
def get_length(list_of_strokes):
"""Calculates the length (in m) of the input array of strokes."""
length = 0
for stroke in list_of_strokes:
length += session.query(func.st_length(stroke.geom)).first()[0]
return length
def construct_stroke(road_section, junction, delimited_stroke, level=1):
"""Constructs a delimited stroke from road_section, with junction as its starting point.
If a delimited_stroke is given as input, the next road_section is added to this delimited_stroke."""
session.flush()
# the delimited stroke dictionary use here is based on type of the input stroke
if type(delimited_stroke) == DelimitedStrokeRef:
delimited_strokes = delimited_strokes_ref
else:
delimited_strokes = delimited_strokes_target
road_section.delimited_stroke = delimited_stroke
# determine which from which junction the next road section should be added
if junction == road_section.begin_junction:
next_junction = road_section.end_junction
else:
next_junction = road_section.begin_junction
# if the next_junction is the same as the begin_junction of the delimited stroke, it is a loop and can be returned
if next_junction.id == delimited_stroke.begin_junction_id:
delimited_stroke.end_junction_id = next_junction.id
return delimited_stroke
# if the degree of the next junction is 2, the road section that is not equal to the input is added
# to the delimited stroke
if next_junction.degree == 2:
for next_road_section in next_junction.road_sections:
if next_road_section != road_section:
delimited_stroke.geom = session.query(
func.st_linemerge(
func.st_collect(delimited_stroke.geom,
next_road_section.geom)))
delimited_strokes[delimited_stroke.id].append(
next_road_section)
return construct_stroke(next_road_section, next_junction,
delimited_stroke, level)
# only strokes at level 1, are extended with sections that have good continuity
if level == 1:
if next_junction.type_k3 == 2:
current_angle = angle_at_junction(road_section, next_junction)
if current_angle != next_junction.angle_k3:
# select the next section that has good continuity
for next_road_section in next_junction.road_sections:
if next_road_section != road_section and next_road_section.delimited_stroke is None:
next_angle = angle_at_junction(next_road_section,
next_junction)
if next_angle != next_junction.angle_k3:
# if the next section is a loop, it is not added to the delimited stroke
if next_road_section.begin_junction == next_road_section.end_junction:
delimited_stroke.end_junction_id = next_junction.id
return delimited_stroke
# merge the selected section with the existing delimited stroke to extend it
delimited_stroke.geom = session.query(
func.st_linemerge(
func.st_collect(delimited_stroke.geom,
next_road_section.geom)))
delimited_strokes[delimited_stroke.id].append(
next_road_section)
return construct_stroke(next_road_section,
next_junction,
delimited_stroke, level)
# if the stroke is not extended, the end junction is set
delimited_stroke.end_junction_id = next_junction.id
return delimited_stroke
def get_distance(object_a, object_b):
"""Calculates the distance between two geometries."""
assert object_a.geom is not None
assert object_b.geom is not None
return session.query(func.st_distance(object_a.geom, object_b.geom))[0][0]
def extend_matching_pair(stroke_ref, stroke_target, junction_ref,
junction_target, tolerance_distance):
"""Extends the input delimited strokes with strokes that have good continuity at input junction,
until a good match is found or if no match is possible. Stroke_ref and stroke_target are both lists of delimited
strokes."""
# create local variables of which stroke to extend and which to compare to when a new stroke is added
if get_length(stroke_ref) < get_length(stroke_target):
stroke_to_extend = stroke_ref
stroke_to_compare = stroke_target
junction_to_extend = junction_ref
junction_to_compare = junction_target
else:
stroke_to_extend = stroke_target
stroke_to_compare = stroke_ref
junction_to_extend = junction_target
junction_to_compare = junction_ref
new_stroke = None
# if the junction where the next stroke is added is a W-junction (type 1), select the stroke of the outer road
# sections to be added
if junction_to_extend.type_k3 == 1:
if angle_at_junction(
stroke_to_extend[-1],
junction_to_extend) != junction_to_extend.angle_k3:
for road_section in junction_to_extend.road_sections:
if road_section.delimited_stroke != stroke_to_extend[-1] and junction_to_extend.angle_k3 != \
angle_at_junction(road_section, junction_to_extend):
new_stroke = road_section.delimited_stroke
# for other junctions, select the stroke that has good continuity
if junction_to_extend.degree > 1:
for road_section in junction_to_extend.road_sections:
if road_section.delimited_stroke != stroke_to_extend[
-1] and has_good_continuity(road_section,
stroke_to_extend[-1],
junction_to_extend):
new_stroke = road_section.delimited_stroke
if new_stroke and (new_stroke.begin_junction == junction_to_extend
or new_stroke.end_junction == junction_to_extend):
stroke_to_extend.append(new_stroke)
junction_to_extend = other_junction(stroke_to_extend[-1],
junction_to_extend)
point_distance = session.query(
func.st_distance(junction_to_extend.geom,
junction_to_compare.geom))[0][0]
if point_distance < tolerance_distance:
return Match(stroke_ref, stroke_target)
elif session.query(func.st_distance(junction_to_extend.geom, stroke_to_compare[-1].geom))[0][0] < tolerance_distance or \
session.query(func.st_distance(junction_to_compare.geom, stroke_to_extend[-1].geom))[0][0] < tolerance_distance:
if stroke_to_extend == stroke_ref:
return extend_matching_pair(stroke_ref, stroke_target,
junction_to_extend,
junction_target,
tolerance_distance)
elif stroke_to_extend == stroke_target:
return extend_matching_pair(stroke_ref, stroke_target,
junction_ref, junction_to_extend,
tolerance_distance)
else:
print('Error: wrong stroke')
return None
def nearby_junctions(junction_ref, tolerance_distance):
"""Finds the junctions in the target database that are within the tolerance distance of junction_ref."""
junctions = session.query(JunctionTarget).filter(
func.st_dwithin(JunctionTarget.geom, junction_ref.geom,
tolerance_distance))
return junctions
