The subway directions provided by Google are quite different from GypsyMaps.  The key difference is that their system is based on exact subway schedules and mine works by approximate frequencies.  One might think that exact schedules would be better, but that may not be the case.  In my experience, the Subways don’t run on an exact schedules unless you are very close to the end points of the lines.  Google’s system at times suggests crazy routes that rely on catching a transfer at exactly the right time.  For instance, on a route I take often, Grand & Allen to 86th & Lex, Google will suggest taking a downtown 6 at Bleeker, to get the uptown 5 at Brooklyn Bridge.  This makes sense if the transfer from the 6 to the 5 really is only 1 minute, but I am not that lucky.

The biggest advantage to doing the routing by frequency is that you can calculate “composite” routes.  For instance, GypsyMaps will often tell you to take the “4 or the 5 train”, which is a more natural way to give directions.

It will be interesting to find out how close the Subway runs to a schedule.  I am going to track it for a few weeks, and I’ll post the results here.

I pushed through a bunch of fixes to the routing. The path finding should be a little smarter now. A big thanks to David, Scott, John, Michael, Lincoln, Niki, and Matthew.

I’ll be posting updates to this blog as I make changes to the site. I look forward to hearing your thoughts or feedback.