def classify_locations_by_intersection(conn):
curs = conn.cursor()
curs.execute("""select latitude, longitude, time, intersection from
location where bus_id = 234105 order by time""")
intersections = []
locations = []
for result in curs.fetchall():
latitude, longitude, time, intersection = result
location = (latitude, longitude)
point = dict(latitude=latitude,
longitude=longitude,
distance=st_line_locate_point(route, location),
time=time)
if intersection:
intersections.append(point)
else:
locations.append(point)
prev_intersection = intersections[0]
next_intersection = intersections[1]
i = 1
rejected = 0
accepted = 0
start_time = locations[0]['time']
for point in locations:
if point['time'] < prev_intersection['time']:
continue #silently reject because it is temporally before the bus starts
while point['time'] > next_intersection['time']:
#advance intersections to match time
prev_intersection = next_intersection
i += 1
if i < len(intersections):
next_intersection = intersections[i]
break
#check distance against intersection distances
if prev_intersection['distance'] <= point['distance'] <= next_intersection['distance']:
accepted += 1
style = "accepted"
else:
rejected += 1
style = "rejected"
print """
<Placemark>
<name>%s - %s</name>
<styleUrl>#%s</styleUrl>
<Point>
<coordinates>
%s, %s
</coordinates>
</Point>
</Placemark>
""" % (point['time'] - start_time, style, style, point['longitude'], point['latitude'])
print "</Document></kml>"
print >>sys.stderr, "accepted, rejected, total", accepted, rejected, len(locations)
def find_shape_by_stops(feed, candidate_routes, stops, table_name):
"""This is brutal -- it matches a set of route paths against a
known set of bus stops to choose the route path which falls
nearest to the trip."""
key = freeze([candidate_routes, stops, table_name])
if key in _shape_by_stops_cache:
return _shape_by_stops_cache[key]
best_route = None
best_dist = 100000000000000
#routes are sorted by length, because we want to use the shortest
#route that matches the points.
for route in sorted(candidate_routes, key=lambda route:route.the_geom.length):
total_dist = 0
for stop in stops:
total_dist += route.the_geom.distance(Point(stop.stop_lon, stop.stop_lat))
if total_dist < best_dist:
best_dist = total_dist
best_route = route
if candidate_routes[0].route == 'S55':
print "The MTA's route shape for S55 is from 2007. So we're skipping it."
return None
if candidate_routes[0].route == 'Q48':
#this is a total hack; the Q48 is in general a total hack
if len(stops) == 22:
for route in candidate_routes:
if route.gid == 10707:
best_route = route
#figure out if the set of stops is shorter than the best route
#(the bus stops or ends in the middle of the route) and if so,
#cut the route down.
start_location = st_line_locate_point(best_route.the_geom, (stops[0].stop_lon, stops[0].stop_lat))
end_location = st_line_locate_point(best_route.the_geom, (stops[-1].stop_lon, stops[-1].stop_lat))
if start_location > end_location:
print "Backwards route %s, Skipping." % route.gid
return None
if end_location - start_location < 0.98 and best_route.route not in loop_routes:
if end_location - start_location < 0.05:
print """"This is a very short route segment. Is it a
miscategorized loop? Route: %s, first and last: %s, %s""" % (
best_route.route, stops[0].location, stops[-1].location)
#create a new shape for the short route
i = 0
while 1:
new_gid = str(best_route.gid * 100 + 20000 + i)
i += 1
try:
feed.GetShape(new_gid)
except KeyError:
break
shape = transitfeed.Shape(new_gid)
#while a binary search for start and end would probably be
#faster, it assumes that the shapes are correctly plotted in
#ascending order, which they appear not to be.
distance = 0
for point in best_route.the_geom.coords:
last_distance = distance
distance = st_line_locate_point(best_route.the_geom, point)
if start_location <= distance - 0.001:
if distance <= end_location + 0.001:
shape.AddPoint(point[1], point[0])
else:
line_distance_span = distance - last_distance;
end_distance_span = end_location - last_distance;
interp_ratio = end_distance_span / line_distance_span
interp_x = last_point[1] * interp_ratio + point[1] * (1 - interp_ratio)
interp_y = last_point[0] * interp_ratio + point[0] * (1 - interp_ratio)
shape.AddPoint(interp_x, interp_y)
last_point = point
feed.AddShapeObject(shape)
else: #not a too-short route
try:
shape = feed.GetShape(str(best_route.gid))
except KeyError:
shape = transitfeed.Shape(str(best_route.gid))
for point in best_route.the_geom.coords:
shape.AddPoint(point[1], point[0])
feed.AddShapeObject(shape)
_shape_by_stops_cache[key] = shape
return shape