Arrivals and Departures to Connections

Status: not functional - work in progress

This javascript library transforms a stream of "arrivals and departures" to "connections".

This code is useful for route planning applications where arrivals and departures are easy to generate, but connections are difficult to get right in the same processing.

Install and use

CLI

npm install -g arrdep2connections

Now you can use the code on top of 2 files which follow the JSON-LD stream specification:

arrdep2connections arrivalsfile.json departurefile.json -i context.json > connections.json

Optionally, you can specify a different inbound context.json using the -i flag, and a different outbound context by using the -o flag.

NodeJS library

Install it using npm:

npm install --save arrdep2connections

Use it in your code:

var arrdep2connections = require('arrdep2connections');
var stringify = require('JSONStream').stringify(false);

departureStream.pipe(arrdep2connections(arrivalStream)).pipe(stringify).pipe(process.stdout);

Data models

1. Arrival objects and departure objects

A departure is something of this form:

{
  "date" : "2015-12-25",
  "departureTime" : "23:49",
  "stop" : "{stop1}",
  "other properties" : "other values"
}

Explanation:

property	URI	description	type
date	dcterms:date	date when the trip of the vehicle departed	a day in ISO8601 format or xsd:date
departureTime	gtfs:departureTime	departure time given as a duration calculated starting at noon minus 12h in this format "hh:mm"	iso8601 or xsd:duration
stop	gtfs:stop	stop of departure	an identifier of the stop of departure
other properties		Feel free to add anything on here. When properties overlap with an arrival, only the property from the departure is kept in the connection.

An Arrival is something of this form:

{
  "date" : "2015-12-25",
  "arrivalTime" : "24:16",
  "stop" : "{stop2}",
  "other properties" : "other values"
}

Explanation:

property	URI	description	type
date	dcterms:date	date when the trip of the vehicle departed	a day in ISO8601 format or xsd:date
arrivalTime	gtfs:arrivalTime	arrival time given as a duration calculated starting at noon minus 12h in this format "hh:mm"	iso8601 or xsd:duration
stop	gtfs:stop	stop of arrival	an identifier of the stop of arrival
other properties		Feel free to add anything on here. When properties overlap with a departure, only the property from the departure is kept in the connection.

2. A connection object

A connection object is something that looks like this:

{
  "departureTime" : "2015-12-25T23:49",
  "departureStop" : "{stop1}",
  "arrivalTime" : "2015-12-26T00:16",
  "arrivalStop" : "{stop2}",
  "other properties" : "other values"
}

Explanation:

property	URI	description	type
arrivalTime	lc:arrivalTime	arrival date/time	iso8601 or xsd:dateTime
arrivalStop	lc:arrivalStop	stop of arrival	an identifier of the stop of arrival
departureTime	lc:departureTime	departure date/time	iso8601 or xsd:dateTime
departureStop	lc:departureStop	stop of departure	an identifier of the stop of departure
other properties		copied properties from the arrival/departure objects