Sunday, February 5, 2012

What it looks like when something ain't right

Tamra Reynolds was pretty persistent on the Quest Facebook page about asking why Hugh Neff's data looked weird.  She made a good catch that a lot of us didn't see - if Hugh really did park on Eagle Summit for 90 minutes, it was very unlikely he could have traveled fast enough to come into Central so close behind Brent Sass.  Something was wrong, but what?

If we'd taken a good look at the race flow chart it would have been clear immediately what the nature of the problem was:

but we didn't, so we didn't see that according to the data coming out of Trackleaders, Hugh traveled the section of trail between shortly before mile 120 to shortly after mile 140 at over 20mph.  He's got a fast team, but not that fast.  So, the possibilities were:

  1. he covered that distance in more time than it shows,
  2. he covered a shorter distance in the time period shown, 
  3. Trackleaders's software is buggy, or
  4. he actually does have an insanely fast team
The fourth option seems impossible.  I tend to have a lot of faith in the Spot devices's reports of time and location so I tended to rule out the second option.  The third option seemed possible but unlikely, given their history of delivering just this sort of information very reliably, and to be honest the first option seemed unlikely as well, given the reliability of the Spot trackers.  

Well, as usual it turned out to be a very real-world, physical error.  Hugh apparently had a wild ride down the back side of Eagle and dropped his tracker, only to be reunited with it later.  Mystery solved.

This does point up once again how good data visualization tools allow us to take in a lot of information with just one glance.

1 comment:

  1. Hi Melinda,

    I enjoy your posts. I have followed the Quest for years, using spreadsheets mostly but recently the GPS has changed a lot of how we predict arrival times etc.

    Here is a question. At race mile 144 on the race flow chart there are several mushers that have little plateaus - mostly two points. Now this might be a short stop, but these occur 4 miles past Central where teams getting drop bags stopped a short time that look just like these little plateaus too. So I thought, okay maybe they go a few miles out the checkpoint and repack or snack or something so the dogs don't get the idea they are staying at the checkpoint. After a few more teams did the exact same thing in the exact same spot I wondered about the reality? Could all these teams be doing the same thing in the same spot?

    I looked on the map to see were mile 144-5 was and it's on the road to the hotsprings - okay? I then checked a few mushers individual tracks to see where they had stopped, should be two points together right? Well I did not find them, just a string of points 10-minutes apart, seemed normal.

    So are these short plateaus a glitch? We might have to be careful not to interpret too much from these if they cannot be proved otherwise?


    regards, Darren in Whitehorse, YT