OTP to Everywhere

otpeverywhere.py

#!/usr/bin/python

# otpeverywhere - make otp maps like 
# http://www.flickr.com/photos/walkingsf/6536396399/

#   Copyright 2011 Matt Conway

#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

# Use the new, Python 2.7/3 argument parser
import argparse
from urllib2 import Request, urlopen
from psycopg2 import connect
from time import time
import json

parser = argparse.ArgumentParser(description="OTP Everywhere Maps")

parser.add_argument('-o', '--out-table', dest='outtable', type=str,
                    help='the table to store data in', action='store',
                    metavar='TABLE', default='otpeverywhere')
parser.add_argument('-i', '--in-table', dest='intable', type=str, action='store',
                    help='the table to retrieve destinations from',
                    metavar='TABLE', default='intersections')
parser.add_argument('-d', '--dsn', dest='dsn', type=str,
                    help='database dsn, as documented at http://initd.org/psycopg/docs/module.html#psycopg2.connect',
                    metavar='DSN', default='dbname=otp')
parser.add_argument('--otp-url', '-u', action='store', dest='otpurl',
                    help='your OTP base URL, default: http://localhost:8080/opentripplanner-api-webapp', 
                    default='http://localhost:8080/opentripplanner-api-webapp')
parser.add_argument('--start', '-s', action='store',
                    help='the start lat,lon (WGS84)', 
                    default='37.7847,-122.40766') # Market and Powell, downtown San Francisco, CA
parser.add_argument('--date', '-a', action='store',
                    help='date, format mm/dd/yyyy',
                    default='12/29/2011')
parser.add_argument('--time', '-t', action='store',
                    help='start time', 
                    default='9:00 am')
parser.add_argument('--mode', '-m', action='store',
                    help='mode, e.g. TRANSIT,BICYCLE',
                    default='TRANSIT,WALK')

opts = parser.parse_args()

# Need two connections b/c named cursor is invalidated on commit
conn = connect(opts.dsn)
inconn = connect(opts.dsn)
incursor = inconn.cursor(name='input')
outcursor = conn.cursor()

# From http://seewah.blogspot.com/2009/11/gpolyline-decoding-in-python.html
def decode_line(encoded):

    """Decodes a polyline that was encoded using the Google Maps method.

    See http://code.google.com/apis/maps/documentation/polylinealgorithm.html
    
    This is a straightforward Python port of Mark McClure's JavaScript polyline decoder
    (http://facstaff.unca.edu/mcmcclur/GoogleMaps/EncodePolyline/decode.js)
    and Peter Chng's PHP polyline decode
    (http://unitstep.net/blog/2008/08/02/decoding-google-maps-encoded-polylines-using-php/)
    """

    encoded_len = len(encoded)
    index = 0
    array = []
    lat = 0
    lng = 0

    while index < encoded_len:

        b = 0
        shift = 0
        result = 0

        while True:
            b = ord(encoded[index]) - 63
            index = index + 1
            result |= (b & 0x1f) << shift
            shift += 5
            if b < 0x20:
                break

        dlat = ~(result >> 1) if result & 1 else result >> 1
        lat += dlat

        shift = 0
        result = 0

        while True:
            b = ord(encoded[index]) - 63
            index = index + 1
            result |= (b & 0x1f) << shift
            shift += 5
            if b < 0x20:
                break

        dlng = ~(result >> 1) if result & 1 else result >> 1
        lng += dlng

        array.append((lat * 1e-5, lng * 1e-5))

    return array

# I know, SQL injection, but you can't have psycopg escape a table name properly
# I think the source is safe, unless you install the script suid postgres or something
incursor.execute('SELECT X(transform(the_geom, 4326)) as lon, Y(transform(the_geom, 4326)) as lat FROM ' + opts.intable)
start_time = time()
i = 0
for geom in incursor:
    # build the url
    url  = '%s/ws/plan' % opts.otpurl
    url += '?fromPlace=%s' % opts.start
    url += '&toPlace=%s,%s' % (geom[1], geom[0])
    url += '&date=%s' % opts.date
    url += '&time=%s' % opts.time.replace(' ', '%20')
    url += '&arriveBy=false'
    url += '&mode=%s' % opts.mode
    url += '&numItineraries=1'

    # Request JSON format
    headers=dict(Accept='application/json')

    # the user doesn't review the request, so it's technically unverifiable
    r = Request(url, headers=headers, unverifiable=True)
    
    # Parse the response
    d = json.loads(urlopen(r).read())

    # Build an array of lat,lon
    points = []

    # Were there errors? If so, d['plan'] == None
    if d['plan']:
        # parse the geometries. also add the times.
        for leg in d['plan']['itineraries'][0]['legs']:
            legPoints = decode_line(leg['legGeometry']['points'])
            assert len(legPoints) == leg['legGeometry']['length']
            points += legPoints
            
        wkt = 'SRID=4326;LINESTRING(%s)' % ', '.join(['%s %s' % (point[1], point[0]) for point in points])
        # ms -> s
        totalTime = (d['plan']['itineraries'][0]['endTime'] - d['plan']['itineraries'][0]['startTime'])/1000
            
        outcursor.execute('INSERT INTO ' + opts.outtable + ' (the_geom, time) VALUES (ST_GeomFromEWKT(%s), %s)', (wkt, totalTime))
    
    else:
        print 'Location %s, %s is unreachable, skipping' % (geom[1], geom[0])
        print d['error']['msg']

    i += 1
    if i % 100 == 0:
        conn.commit()
        newtime = time()
        print '100 requests, %s seconds, average %s secs/request' % (newtime - start_time, (newtime - start_time)/100)
        start_time = newtime