This is just a fan letter about the maps-and-directions software that I guess has been in GPS products for years and is now on every Internet-capable phone.
I’m a little too close to most technology, particularly the sort you get over the Net: either I can see the glitches and flaws, or I can see how I could have built it myself, in principle. But not the directions-to-anywhere stuff; to me, it’s pure black magic. I have no idea what the inputs are, what sort of data structures you build with them, or what sort of algorithms you’d use to compute the directions.
The other day we were off to visit a friend in a remote corner of Surrey — one of Vancouver’s big medium-distant suburbs. We also had to stop at this particular mall to pick up a couple of things. The problem was, getting ready to leave the mall parking, I found a big blank space in my mind where the route from the mall to southwest Surrey should be. A glance at the map-book seemed to suggest doubling back about thirty blocks to a through road. About 30 seconds with the Maps app on the NexusOne suggested a non-obvious couple of turns leading to a road I’d never even heard mentioned on the traffic broadcasts that dumped us onto the approaches to the right bridge.
It was at that point that I realized I had no idea how it was done. I still don’t. Which bothers me a little, but I sure enjoy the results.