pyTransition 0.1.2

A Python package to interact with the Transition API.

pyTransition

pyTransition is a Python package designed to interact with the public API of the transit planning application Transition. It allows users to retrieve and request geographic and routing data from the app.
The documentation for the Transition public API used by this library can be found here

Install and import pyTransition

To install pyTransition, use the following command :

pip install pyTransition

After installing pyTransition, it may be imported into Python code like :

from pyTransition import Transition

Usage

pyTransition allows users to send HTTP requests. Before requesting data, users must first request a token. This is done using the request_token method. Afterwards, users can either set the token and server URL for the current instance using the set_token and set_url methods. The token and URL will be stored as local variables for the duration of the script only. Alternatively, users can send the token and the URL as parameters directly when calling methods.

To use the library, users first need to instantiate the Transition class with the necessary connection information, by using the class constructor. The following class methods will then be available to use from the Transition instance :

Transition constructor :

There are 2 ways to use the Transition class constructor.

1. To login with their username/email and password, users need to provide the Transition server URL, their username/email and their password like this :

   transition_instance = Transition("http://localhost:8080", "username", "password")
   

2. To login with an already known Transition API authentication token, users can provide only the Transition server URL and their token. In this case, users have to set the values for the username and password parameters to None like this :

   transition_instance = Transition("http://localhost:8080", None, None, "token")
   

Parameters : url : string
        The Transition server base URL.
       username : string
        The username (or email) used for login.
       password : string
        The password used for login.
       token (optional, default value None) : string
        The Transition API authentication token.

Returns :   result : Transition
        An instance of the Transition Python class.

Raises :   ValueError
        If the url parameter is empty.

get_paths :

This method allows users to fetch all paths which are currently loaded in the Transition application. In case of a successful request, the paths are returned in JSON format.

Parameters : url : string
        The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : GeoJSON
        All paths currently loaded in the Transition application in GeoJSON format

Raises :   RequestException
        If response code is not 200.

get_nodes :

This method allows users to fetch all nodes which are currently loaded in the Transition application. In case of a successful request, the nodes are returned in JSON format.

Parameters : url : string
        The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : GeoJSON
        All nodes currently loaded in the Transition application in GeoJSON format.

Raises :   RequestException
        If response code is not 200.

get_scenarios :

This method allows users to fetch all scenarios which are currently loaded in the Transition application. In case of a successful request, the scenarios are returned in JSON format. The scenarios are needed in order to request calculations for new routes or accessibility maps.

Parameters : url : string
        The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : JSON
        All scenarios currently loaded in the Transition application in JSON format.

Raises :   RequestException
        If response code is not 200.

get_routing_modes :

This method allows users to fetch all routing modes which are currently loaded in the Transition application. In case of a successful request, a list of routing modes is returned. The routing modes are needed in order to request calculations for new routes.

Parameters : url : string
        The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : list
        All routing modes currently loaded in the Transition application.

Raises :   RequestException
        If response code is not 200.

get_routing_result:

This method allows users to send calculation parameters to the Transition server to request a new route. The request can be made for different transit modes. In case of a successful request, the new route is returned in JSON format.
Parameters : modes : list
         Transit modes for which to calculate the routes.
       origin : list
         Origin coordinates. Must be sent as [longitude, latitude]
       destination : list
         Destination coordinates. Must be sent as [longitude, latitude]
       scenario_id : string
         ID of the used scenario as loaded in Transition application.
       departure_or_arrival_choice : string
         Specifies whether the used time is "Departure" or "Arrival".
       departure_or_arrival_time : Time
         Departure or arrival time of the trip.
       max_travel_time : int
         Maximum travel time including access, in minutes.
       min_waiting_time : int
         Minimum waiting time, in minutes.
       max_transfer_time : int
         Maximum transfer time, in minutes.
       max_access_time : int
         Maximum access time, in minutes.
       max_first_waiting_time : int
         Maximum wait time at first transit stop, in minutes.
       with_geojson : bool
         If True, the returned JSON file will contain the "pathsGeojson" key for each mode containing the GeoJSON geometry.
       url : string
         The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : JSON
         Route for each transit mode in JSON format.

Raises : RequestException
       If response code is not 200.

get_accessibility_map

This method allows users to send accessibility map parameters to the Transition server to request a new accessibility map. In case of a successful request, the accessibility map is returned in JSON format.
Parameters : coordinates : list
         Coordinates of the starting point of the accessibility map. Must be sent as [longitude, latitude]
       scenario_id : string
         ID of the used scenario as loaded in Transition application.
       departure_or_arrival_choice : string
         Specifies whether the used time is "Departure" or "Arrival".
       departure_or_arrival_time : Time
         Departure or arrival time of the trip.
       n_polygons : int
         Number of polygons to be calculated
       delta_minutes : int
         Baseline delta used for average accessibility map calculations.
       delta_interval_minutes : int
         Interval used between each calculation.
       max_total_travel_time_minutes : int
         Maximum travel time, in minutes.
       min_waiting_time_minutes : int
         Minimum waiting time, in minutes.
       max_access_egress_travel_time_minutes : int
         Maximum access time, in minutes.
       max_transfer_travel_time_minutes : int
         Maximum transfer time, in minutes.
       max_first_waiting_time_minutes : bool
         Maximum wait time at first transit stop, in minutes.
       walking_speed_kmh : int
         Walking speed, in km/h
       with_geojson : bool
         If True, the returned JSON file will contain geometry information for the strokes and polygons of the accessibility map.
       url : string
         The server URL where the request is sent.
       token : string
        The token used for user authentication.

Returns :   result : JSON
         Accessibility map information in JSON format.

Raises :   RequestException
       If response code is not 200.

Example

Users can fetch the nodes which are currently loaded in the Transition application using pyTransition as follows :

from pyTransition.transition import Transition

def get_transition_nodes():
    # Create Transition instance from connection credentials
    # The login information can be saved in a file to not have them displayed in the code
    transition_instance = Transition("http://localhost:8080", username, password)

    # Call the API
    nodes = transition_instance.get_nodes()

    # Process nodes however you want. Here, we are just printing the result
    print(nodes)

Fetching the paths can be done in the same way, by replacing get_nodes() with get_paths().

Alternatively, if the user already knows their Transition API authentication token, they can create the instance with it directly, as follows :

from pyTransition.transition import Transition

def get_transition_nodes():
    # Create Transition instance from authentication token
    # The login information can be saved in a file to not have them displayed in the code
    transition_instance = Transition("http://localhost:8080", None, None, token)

    # Call the API
    nodes = Transition.get_nodes()

    # Process nodes however you want. Here, we are just printing the result
    print(nodes)

Another example using pyTransition to get a new accessibility map :

from pyTransition.transition import Transition
from datetime import time
import json

def get_transition_acessibility_map():
    # Create Transition instance from connection credentials
    transition_instance = Transition("http://localhost:8080", username, password)

    # Get the scenarios. A scenario is needed to request an accessibility map
    scenarios = transition_instance.get_scenarios()

    # Get the ID of the scenario we want to use. Here, we use the first one 
    scenario_id = scenarios['collection'][0]['id']

    # Call the API
    accessibility_map_data = transition_instance.request_accessibility_map(
                coordinates=[45.5383, -73.4727],
                departure_or_arrival_choice="Departure",
                departure_or_arrival_time=time(8,0), # Create a new time object representing 8:00
                n_polygons=3,
                delta_minutes=15,
                delta_interval_minutes=5,
                scenario_id=scenario_id,
                max_total_travel_time_minutes=30,
                min_waiting_time_minutes=3,
                max_access_egress_travel_time_minutes=15,
                max_transfer_travel_time_minutes=10,
                max_first_waiting_time_minutes=0,
                walking_speed_kmh=5,
                with_geojson=True,
            )

    # Process the map however you want. Here, we are saving it to a json file
    with open("accessibility.json", 'w') as f:
        f.write(json.dumps(accessibility_map_data))

Another example using pyTransition to get a new routes :

from pyTransition.transition import Transition
from datetime import time
import json

def get_transition_routes():
    # Create Transition instance from connection credentials
    # The login information can be saved in a file to not have them displayed in the code
    transition_instance = Transition("http://localhost:8080", username, password)

    # Get the scenarios and routing modes. A scenario and at least one routing mode
    # are needed to request an new route
    scenarios = transition_instance.get_scenarios()
    routing_modes = transition_instance.get_routing_modes()

    # Get the ID of the scenario we want to use. Here, we use the first one 
    scenario_id = scenarios['collection'][0]['id']
    # Get the modes you want to use. Here, we are usisng the first two ones
    # You can print the modes to see which are available
    modes = routing_modes[:2]
    

    # Call the API
    routing_data = transition_instance.request_routing_result(
                modes=modes, 
                origin=[-73.4727, 45.5383], 
                destination=[-73.4499, 45.5176], 
                scenario_id=scenarioId, 
                departure_or_arrival_choice=departureOrArrivalChoice, 
                departure_or_arrival_time=departureOrArrivalTime, 
                max_travel_time_minutes=maxParcoursTime, 
                min_waiting_time_minutes=minWaitTime,
                max_transfer_time_minutes=maxTransferWaitTime, 
                max_access_time_minutes=maxAccessTimeOrigDest, 
                max_first_waiting_time_minutes=maxWaitTimeFisrstStopChoice,
                with_geojson=True,
                with_alternatives=True
            )

    # Process the data however you want.
    # For example, we can get the geojson paths of each transit mode in a loop
    for key, value in routing_data.items():  
        # Get the number of alternative paths for the current mode
        geojsonPaths = value["pathsGeojson"]
        mode = key
        # For each alternative, get the geojson associated
        for i in range(len(geojsonPath)):
            geojson_data = geojsonPath[i]
            # Process however you want. Here we are just printing it.
            print(geojson_data)

    # We can also save it to a json file
    with open("routing.json", 'w') as f:
        f.write(json.dumps(routing_data))