Thursday, February 7, 2013

A bit more on the race flow chart

If you look at the Trackleaders map for the Quest, it's pretty easy to see how far apart two teams are, at least in theory.  You can look at the map, click on the icon for the team, and a window pops up that tells you, among other things, the trail miles for that team.  For example,

So, you can get the trail miles for each team, take the difference, and know how far they are apart.

But it's got its limitations.  One is that it's pretty easy to overlook the timestamp on the "breadcrumb" (GPS reading), and if it's more than 20 minutes old or so it can be misleading (especially if you're comparing two teams with timestamps of much different ages).  The other issue is related to the first, and that's that you don't get much sense of the race flow, or the dynamics of teams moving down the trail and their relationship to each other.  This is one of the reasons that I like the race flow chart - it tells the story of the race rather than just showing you static points on a map.  So right now (8:25 AKST, Thursday evening), we can see where Hugh and Allen are but the race flow chart can tell us more about how their relationship is changing as they travel.  And you can nail it down pretty easily.  Here's an example:

In this screen grab, I've drawn black horizontal lines for Hugh and Allen at two different times, the first at race hour 126 (the x-axis on the chart is hours since the race start, and y-axis on the chart is trail mile) and the second at hour 129.  A horizontal line across a given time will intersect the y-axis at a trail mile.  So, at hour 126 it looks like Allen is roughly at mile 511, and Hugh is at mile 518.5 (that level of granularity is more obvious when you scroll in more closely).  So, there's about 7.5 miles between them.  If you look at where they are at hour 129, you can eyeball it and see that the distance between them has closed a bit, but you can be a bit more exact by seeing what mile they're at.  It looks like Allen is at about mile 534 and Hugh is at about mile 540.  In other words, the distance between them is now roughly six miles, and the gap has closed by about 1.5 miles over three hours, or about .5 mph.

And you can play with it further - project the lines to see where they'd cross, etc.  But mostly it's a terrific tool for illustrating that the teams aren't just points on a map - they're moving through time and space, and where they are in relationship to each other is constantly changing.

No comments:

Post a Comment