Information Technology Reference
In-Depth Information
Google was a key participant in the evolution of GTFS-Realtime, which is evident in the
choice of data format selected. Instead of keeping with the comma-separated formats of
the base GTFS standard, GTFS-Realtime adopted Google's protocol buffer format. This
is just another data format created with the ideals of efficient platform-neutral
serialization and deserialization in mind—basically a terse parallel to XML. In practice,
this just means one needs to refer to a protocol buffer definition to determine field
lengths and attributes within the text/data.
Exploring GTFS Examples
Our chapter is already getting long in the tooth, and introducing and exploring even a
small GTFS example will run to many hundreds of lines of JavaScript, HTML, and CSS.
This isn't because the examples are difficult or complex, but rather, because they need
to deal with all of the geolocation and map rendering style code we've already worked
with in this chapter, as well as a fair chunk of text processing code and I/O code to deal
with sourcing and processing the GTFS data.
There'd be enough material for a separate book in its own right, so rather than swamp
our topic with such a large detour, we'll instead call out some excellent publicly available
examples online, that you can download and explore to your heart's content to discover
more about GTFS and its possibilities.
Some of the notable, and very useful, open source examples of GTFS available online
include:
Google's Transit Developers Page
As an active member of the GTFS
community, Google has a wealth of examples available online. Point your
The One Busway Project
Originally founded by developers in Puget
Busway Project that has expanded to a global initiative for GTFS
developers.
Community Projects
like UlmApi.de's Live Map, the result of a
hackathon that built a fully functional GTFS-based transit app in just a
few hours. Full project details are available at
In Figure 10-5, you can see the complete transport system in early morning Ulm, as
rendered by the UlmApi.de web application for Android.
