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Matching.py
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Matching.py
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import java.lang.Object
from interfaces import MatchingType
from Map import *
from Utils import DistancePointLine, lineMagnitude
import psycopg2
#!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#Be Cautious!!
#Psycopg2 doesn't support Jython, so you have to find another way in order to save and obtain shortest path information without psycopg2!
#!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
import time
import math
import os
class TrajPoint(object):
def __init__(self, devicesn, timestamp, lon, lat, spd):
self.devicesn, self.timestamp, self.lon, self.lat, self.spd= devicesn, timestamp, lon, lat, spd
self.row = self.col = -1
class Matching(MatchingType):
def __init__ (self, search_range = 100):
bjmap = Map()
filenames = ["bjmap/road"]
bjmap.load_roads(filenames)
bjmap.stat_map_info()
bjmap.index_roads_on_grid()
bjmap.gen_road_graph()
self.traj_map = bjmap
self.search_range = search_range
#for constructing a coordinate map in meters
m_latitude = (self.traj_map.min_latitude + self.traj_map.max_latitude) / 2
self.WIDTH = map_dist(self.traj_map.min_longitude, m_latitude, self.traj_map.max_longitude, m_latitude)
m_longitude = (self.traj_map.min_longitude + self.traj_map.max_longitude) / 2
self.HEIGHT = map_dist(m_longitude, self.traj_map.min_latitude, m_longitude, self.traj_map.max_latitude)
print "Connecting..Database: shortest_path..."
self.conn_sp = psycopg2.connect(host='localhost', port='5432', database="mapmatching", user='postgres',password='123456')
print "Connected!"
self.cursor_sp = self.conn_sp.cursor()
self.shortest_path = {}
self.initialize_sp()
self.supp = {}
def __del__ (self):
self.conn_sp.commit()
self.conn_sp.close()
def point_matching(self, devicesn, timestamp, lon, lat, spd):
traj_point = TrajPoint(devicesn, timestamp, lon, lat, spd)
if not self.supp.has_key(traj_point.devicesn):
dsn = traj_point.devicesn
self.supp[dsn] = {}
self.supp[dsn]["prev_traj_point"] = -1
self.supp[dsn]["prev_seg"] = (-1, -1)
self.supp[dsn]["prev_f_candidate"] = []
self.supp[dsn]["prev_prev_seg"] = (-1, -1)
print "MapMatching at Time:", time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(traj_point.timestamp))
#t1 = time.time()
dsn = traj_point.devicesn
candidate = self.obtain_candidate(traj_point)
#t2 = time.time()
#print "Obtain_Candidate spends %f s" % (t2-t1)
#print "Number of Candidates:" , len(candidate)
f_candidate = self.obtain_matching_segment(traj_point, self.supp[dsn]["prev_traj_point"], self.supp[dsn]["prev_seg"], candidate)
road_id = f_candidate[0][1]
seg_id = f_candidate[0][2]
#t3 = time.time()
#print "Obtain_matching_segment spends %f s" % (t3-t2)
#modify backwards
mod_road_id, mod_seg_id = -1, -1
if self.supp[dsn]["prev_seg"] != (-1, -1) and self.supp[dsn]["prev_prev_seg"] != (-1, -1) and (road_id, seg_id) != (-1, -1): #if it is the first and second point or there is no matching result for current point, no need to modify backwards
cur_seg = (road_id, seg_id)
mod_road_id, mod_seg_id = self.modify_backwards(cur_seg, self.supp[dsn]["prev_f_candidate"], self.supp[dsn]["prev_prev_seg"])
#t4 = time.time()
#print "Modify Backwards spends %f s" % (t4-t3)
self.supp[dsn]["prev_traj_point"] = traj_point
self.supp[dsn]["prev_f_candidate"] = f_candidate
if (mod_road_id, mod_seg_id) == (-1, -1) or (mod_road_id, mod_seg_id) == self.supp[dsn]["prev_seg"]:
self.supp[dsn]["prev_prev_seg"] = self.supp[dsn]["prev_seg"]
self.supp[dsn]["prev_seg"] = (road_id, seg_id)
return str(road_id) + '_' + str(seg_id) + '_' + '-1' + '_' + '-1'
else:
self.supp[dsn]["prev_prev_seg"] = (mod_road_id, mod_seg_id)
self.supp[dsn]["prev_seg"] = (road_id, seg_id)
return str(road_id) + '_' + str(seg_id) + '_' + str(mod_road_id) + '_' + str(mod_seg_id)
def obtain_candidate(self, traj_point):
traj_point.row, traj_point.col = self.traj_map.lon_lat_to_grid_row_col(traj_point.lon, traj_point.lat)
row_l = max(0, traj_point.row - 1)
row_h = min(self.traj_map.TOTAL_GRID_ROWS - 1, traj_point.row + 1)
col_l = max(0, traj_point.col - 1)
col_h = min(self.traj_map.TOTAL_GRID_COLS - 1, traj_point.col + 1)
search_set = set()
for i in range(row_l, row_h + 1):
for j in range(col_l, col_h + 1):
search_set = search_set | set(self.traj_map.grid_road_index[i][j])
px, py = self.to_standard_xy(traj_point.lon, traj_point.lat)
candidate = []
for (r,s) in search_set:
x1, y1 = self.to_standard_xy(self.traj_map.roads[r][s][0], self.traj_map.roads[r][s][1])
x2, y2 = self.to_standard_xy(self.traj_map.roads[r][s+1][0], self.traj_map.roads[r][s+1][1])
dist, lx, ly = DistancePointLine(px, py, x1, y1, x2, y2)
if dist < self.search_range:
flag = False
for idx in range(0, len(candidate)):
if(dist < candidate[idx][0]):
candidate.insert(idx, (dist, r, s))
flag = True
break
if flag == False:
candidate.append((dist, r, s))
if len(candidate) > 5: #5 candidates at most
candidate = candidate[:5]
return candidate
def obtain_matching_segment(self, traj_point, prev_traj_point, prev_seg, candidate):
f_tp = []
for (d, r, s) in candidate:
op = self.ObservationProbability(d)
if prev_traj_point == -1 or prev_seg == (-1,-1): #if it is the first point or previous point has no result, then ignore the topological probability
tp = 1
else:
tp = self.TopologicalProbability(r, s, traj_point, prev_traj_point, prev_seg)
result = op*tp
if result > 0:
flag = False
for idx in range(0, len(f_tp)):
if(result > f_tp[idx][0]):
f_tp.insert(idx, (result, r, s))
flag = True
break
if flag == False:
f_tp.append((result, r, s))
if not f_tp:
print "Warning!No Matched Segment!"
f_tp = [(0.0, -1, -1)]
return f_tp
def ObservationProbability(self, d):
MV = 0 #mean value
SD = 20 #standard deviation
op = (1 / math.sqrt(2 * math.pi * SD)) * math.exp(- math.pow(d - MV, 2) / (2 * math.pow(SD, 2)))
return op
def TopologicalProbability(self, r, s, traj_point, prev_traj_point, prev_seg):
prev_x, prev_y = self.to_standard_xy(prev_traj_point.lon, prev_traj_point.lat)
prev_seg_x1, prev_seg_y1 = self.to_standard_xy(self.traj_map.roads[prev_seg[0]][prev_seg[1]][0], self.traj_map.roads[prev_seg[0]][prev_seg[1]][1])
prev_seg_x2, prev_seg_y2 = self.to_standard_xy(self.traj_map.roads[prev_seg[0]][prev_seg[1]+1][0], self.traj_map.roads[prev_seg[0]][prev_seg[1]+1][1])
cur_x, cur_y = self.to_standard_xy(traj_point.lon, traj_point.lat)
cur_seg_x1, cur_seg_y1 = self.to_standard_xy(self.traj_map.roads[r][s][0], self.traj_map.roads[r][s][1])
cur_seg_x2, cur_seg_y2 = self.to_standard_xy(self.traj_map.roads[r][s+1][0], self.traj_map.roads[r][s+1][1])
d1, prev_ix, prev_iy = DistancePointLine(prev_x, prev_y, prev_seg_x1, prev_seg_y1, prev_seg_x2, prev_seg_y2)
d2, cur_ix, cur_iy = DistancePointLine(cur_x, cur_y, cur_seg_x1, cur_seg_y1, cur_seg_x2, cur_seg_y2)
if (r,s) == prev_seg: #if on the same segment
w = lineMagnitude(prev_ix, prev_iy, cur_ix, cur_iy)
else:
tar_prev = (-1,-1)
sp = self.obtain_shortest_path(prev_seg[0], prev_seg[1], r, s)
tar_prev = sp[0:2]
w0 = sp[2]
if w0 == -1: #no shortest_path
return 0
intersection = self.find_intersection(tar_prev[0], tar_prev[1], r, s)
prev_intersection_x, prev_intersection_y = self.to_standard_xy(intersection[0], intersection[1])
tar = (r, s)
while prev_seg != tar_prev:
tar = tar_prev
sp = self.obtain_shortest_path(prev_seg[0], prev_seg[1], tar[0], tar[1])
tar_prev = sp[0:2]
d = sp[2]
intersection = self.find_intersection(tar[0], tar[1], prev_seg[0], prev_seg[1])
latter_intersection_x, latter_intersection_y = self.to_standard_xy(intersection[0], intersection[1])
w = w0 + lineMagnitude(prev_ix, prev_iy, latter_intersection_x, latter_intersection_y) + lineMagnitude(prev_intersection_x, prev_intersection_y, cur_ix, cur_iy) #obtain the length of shortest path
avg_spd = (prev_traj_point.spd + traj_point.spd) / 2.0 * 1000
t = traj_point.timestamp - prev_traj_point.timestamp
if t >= 10.0: #if vehicle didn't move, GPS won't send data, so we have to consider the driving time as 5 seconds
t = 5.0
avg_spd /= 2.0
t = t / 60.0 / 60.0
dist = avg_spd * t
if dist < w:
dist = 2.0 * w - dist
if dist != 0:
tp = 1 - abs(w - dist) / dist
else:
tp = 1
return tp
def modify_backwards(self, cur_seg, prev_f_candidate, prev_prev_seg):
sp = [cur_seg]
tar = cur_seg
while tar != prev_prev_seg:
tar = self.obtain_shortest_path(prev_prev_seg[0], prev_prev_seg[1], tar[0], tar[1])[:2]
if tar == (-1, -1):
return -1, -1
sp.append(tar)
for (f, r, s) in prev_f_candidate:
if (r, s) in sp:
return r, s
return -1, -1
def obtain_shortest_path(self, r1, s1, r2, s2):
if not self.shortest_path.has_key(r1): #move the sp information of src_road to memory from disk
self.shortest_path[r1] = {}
sql = "SELECT src_segmentid, dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist FROM shortest_path WHERE src_roadid = %d" % (r1)
self.cursor_sp.execute(sql)
result = self.cursor_sp.fetchall()
if len(result) == 0:
#print "Failed to obtain shortest path!"
return -1, -1, -1
for (src_segmentid, dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist) in result:
if not self.shortest_path[r1].has_key(src_segmentid):
self.shortest_path[r1][src_segmentid] = []
self.shortest_path[r1][src_segmentid].append((dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist))
if self.shortest_path[r1].has_key(s1):
for (d_r, d_s, p_r, p_s, dst) in self.shortest_path[r1][s1]:
if d_r == r2 and d_s == s2:
return p_r, p_s, dst
return -1, -1, -1
def initialize_sp(self):
print "Initializing Shortest Path List......"
sql = "SELECT src_roadid, src_segmentid, dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist FROM shortest_path"
self.cursor_sp.execute(sql)
result = self.cursor_sp.fetchall()
print len(result)
if len(result) == 0:
#print "Failed to initialize shortest path!"
return -1, -1, -1
for (src_roadid, src_segmentid, dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist) in result:
if not self.shortest_path.has_key(src_roadid):
self.shortest_path[src_roadid] = {}
if not self.shortest_path[src_roadid].has_key(src_segmentid):
self.shortest_path[src_roadid][src_segmentid] = []
self.shortest_path[src_roadid][src_segmentid].append((dst_roadid, dst_segmentid, prev_roadid, prev_segmentid, dist))
print "Shortest Path Initializing Succeed!"
def find_intersection(self, r1, s1, r2, s2):
if r1 == r2 and abs(s1-s2) == 1:
return self.traj_map.roads[r1][max(s1, s2)]
for inters in self.traj_map.road_intersections[r1]:
if inters[2] == s1 and inters[3] == (r2, s2):
return inters[:2]
print "ERROR! Failed to find intersection!!"
return -1, -1
def to_standard_xy(self, lon, lat): #convert longitude, latitude to x,y in meters in the map
x = (lon - self.traj_map.min_longitude) * self.WIDTH / (self.traj_map.max_longitude - self.traj_map.min_longitude)
y = self.HEIGHT - (lat - self.traj_map.min_latitude) * self.HEIGHT/ (self.traj_map.max_latitude - self.traj_map.min_latitude)
return x, y