How Transport for London Website Works

Question

Hi,

Here let me clarify , I have no intentions to peep in to or any evil intention towards tfls database and other related information.

But , ofcourse Millions of users are greatly beniftted the way it serves the information. http://journeyplanner.tfl.gov.uk/

So , If we want to create some site like tfl, journeyplanner , what are the basic things we need to keep in mind.

• Which Architecture We should use?

• Can We create this website using ASP.NET(Should be able to)?

• Is TFL integrating it's website with google maps or any other GPS

Edit:

While you enter the Zip/Pin code or Station name , it creates a map automatically from source to destination and calcculates the distance also.

My Question here is , How do they calculate the distance , do they keep help of Maps or GPS or they created there own webservic?

Answer 1

To answer the points, in order:

Which Architecture We should use?

One you know and understand there is more than one approach that would be possible to do a similar thing with.

Can We create this website using ASP.NET(Should be able to)?

You could. Similarly, you could do it as a Java Servlet or PHP application. If you were feeling particularly warped, you could probably make something work in pure Javascript (but your clients might hate you)

Is TFL integrating it's website with google maps or any other GPS

They're more likely using Ordnance Survey data, that they've rendered their own maps from (certainly if you pan right out, coverage runs out quite quickly).

From a routing perspective, they're probably using something like Dijkstra's Algorithm, although it's probably very optimised to cope with timetabling.

There are numerous algorithms for routing, which boil down to "relative cost" (where that cost may be distance, time, financial, or a combination). Not taking into consideration timetables, you can precalculate the costs between connected nodes (e.g. Liverpool St -> Bank via Central Line is ~5 mins), this would give a baseline for something like Dijkstra although you'd still need to factor in the cost of interchaging between modes of transport and waiting for connections to arrive, etc.).

You might want to look into routing algorithms in general (there's even info over on OpenStreetMap's wiki) before looking into the complexities introduced with timetabled services.