Tracking without trackers

It's a very cool thing that tucked away in some of the most unexpected places are some really clever people doing really clever things.  One of these place is Fort Kent, Maine (pop. ~4000), home of arguably the premier distance dogsled race in eastern North America, the Can-Am Crown.

I mentioned earlier that the first time I ever saw dog teams move on a map while a race was underway was during the Can-Am Crown, some number of years ago.  They showed teams from all three of their races (30, 60, and 250-milers) moving on a topo map.  At first I thought they must have had GPS units on the sleds and had figured out some way to uplink data (this was before IonEarth came up with their hardware, and before Spot started selling commodity trackers).  It turns out that that was not what was happening at all.

My understanding of how it actually works is incomplete but this is what I've got so far:  They use checkpoint arrival times to calculate traveling speeds and then project those onto the map.  I've heard, but can't confirm, that they've got spotters on the trails reporting when teams pass so that they're able to get better granularity on times.  If someone has some more information on how it actually works, I'd be grateful if you could let me know.

You can go back and rerun past races, and it may be worth doing to get used to the user interface, which is not, er, fully intuitive, in preparation for this weekend's Can-Am.

So, here goes!  Go to the race data page, here.  You'll see a crapload of buttons across the top of the page.  The page displays race data for the current year.  If it's before the start of this year's race (Saturday, March 3 2012) you'll no data, but the buttons will be there.  Hit the down arrow button (circled in red in this image) once to get to the 2011 data:

Once there, hit the "TRACK!" button:

This will pop up a topo map with the trail marked in blue and a bunch of little yellow squares representing mushers, Swiss flags representing first aid stations, and big yellow squares representing actual checkpoints:

You can focus in on individual mushers and get data about where they are, their speed, how many dogs they've got, etc., and you can replay the race.  While the user interface takes some getting used to, I think this is a fantastically clever piece of work and the authors deserve major kudos.