def __init__(self):

self.init_db()

def init_db(self):

print "Connecting to database ......"

self.conn_to = psycopg2.connect(host='osm-workspace-2.cfmyklmn07yu.us-west-2.rds.amazonaws.com', port='5432', database='osm', user='ds', password='ds2015')

if self.conn_to:

print "Connected."

self.cursor = self.conn_to.cursor()

def close_db(self):

self.conn_to.commit()

self.conn_to.close()

def locate_links(self, road_name, function_class_numeric):

#find (lon, lat) of (from_node, to_node) of all links on the certain highway

print "Begin locating links on " + road_name

link_loc = {}

if function_class_numeric == 1:

sql = "select link_id, from_node_id, to_node_id from links where function_class_numeric=1 and name_default like '%" + road_name + "%'"

else:

sql = "select link_id, from_node_id, to_node_id from links where function_class_numeric in (3,4) and upper(name_default) like '%" + road_name + "%'"

self.cursor.execute(sql)

nodes = self.cursor.fetchall()

for (link_id, from_node_id, to_node_id) in nodes:

sql = "select ST_AsText(geom) from nodes where node_id =" + str(from_node_id)

self.cursor.execute(sql)

from_node_pos = self.cursor.fetchall()[0][0]

from_node_loc = Utils.extract_loc_from_geometry(from_node_pos)

sql = "select ST_AsText(geom) from nodes where node_id =" + str(to_node_id)

self.cursor.execute(sql)

to_node_pos = self.cursor.fetchall()[0][0]

to_node_loc = Utils.extract_loc_from_geometry(to_node_pos)

link_loc[link_id] = (from_node_loc, to_node_loc)

print "Link locating finished, there are " + str(len(link_loc)) + " links on " + road_name

return link_loc

def filter_bearing(self, link_loc, direction):

#filter all links which have the certain direction

#direction: 0-North 1-South 2-East 3-West

print "Begin filtering links with right direction"

bearing_links = []

for link_id in link_loc:

heading = Utils.bearing(link_loc[link_id][0][0], link_loc[link_id][0][1] , link_loc[link_id][1][0], link_loc[link_id][1][1])

if direction == 0 and (heading > 270 or heading < 90):

bearing_links.append(link_id)

elif direction == 1 and (heading > 90 and heading < 270):

bearing_links.append(link_id)

elif direction == 2 and (heading > 180 and heading < 360):

bearing_links.append(link_id)

elif direction == 3 and (heading > 0 and heading < 180):

bearing_links.append(link_id)

print "After bearing filtering, there are " + str(len(bearing_links)) + " links left"

return bearing_links

def find_start_end_link(self, link_loc, bearing_links, start_lon, start_lat, end_lon, end_lat):

#According to approximate (lon,lat) find closest node and then find the first and the last link

print "Begin finding the first and the last links on the section"

start_closest_dist = 99999

end_closest_dist = 99999

for link_id in bearing_links:

from_node_loc = link_loc[link_id][0]

to_node_loc = link_loc[link_id][1]

start_dist = Utils.map_dist(from_node_loc[0], from_node_loc[1], start_lon, start_lat)

if start_dist < start_closest_dist:

start_link = link_id

start_closest_dist = start_dist

end_dist = Utils.map_dist(to_node_loc[0], to_node_loc[1], end_lon, end_lat)

if end_dist < end_closest_dist:

end_link = link_id

end_closest_dist = end_dist

print "The start node is ", link_loc[start_link][0][1], link_loc[start_link][0][0] , " and the end node is ", link_loc[end_link][1][1], link_loc[end_link][1][0]

return start_link, end_link

def fill_path(self, link_loc, bearing_links, start_link, end_link, direction):

#Find all links between start_link and end_link

print "Begin filling the whole section"

path = []

start_node_loc = link_loc[start_link][0]

end_node_loc = link_loc[end_link][1]

for link_id in bearing_links:

if Utils.map_dist(link_loc[link_id][0][0], link_loc[link_id][0][1], start_node_loc[0], start_node_loc[1]) < 10000:

if direction == 0 and link_loc[link_id][0][1] >= start_node_loc[1] and link_loc[link_id][1][1] <= end_node_loc[1]:

path.append(link_id)

elif direction == 1 and link_loc[link_id][0][1] <= start_node_loc[1] and link_loc[link_id][1][1] >= end_node_loc[1]:

path.append(link_id)

elif direction == 2 and link_loc[link_id][0][0] >= start_node_loc[0] and link_loc[link_id][1][0] <= end_node_loc[0]:

path.append(link_id)

elif direction == 3 and link_loc[link_id][0][0] <= start_node_loc[0] and link_loc[link_id][1][0] >= end_node_loc[0]:

path.append(link_id)

print "Section filling finished"