Wednesday, May 21, 2014

Are GPS Tracks Proof for an FKT?

I used my first GPS unit in 1991 as a student, and later in my job as a GIS programmer I built software to plot the locations of fleet vehicles on maps of their service areas - both in real-time and playback versions of  'breadcrumb trails' showing where they had been. The stored 'breadcrumb' data files would have been easy to manipulate by changing the latitude and longitude of the points, or by changing the date stamps to speed up the route. It might be tedious to do, but it wouldn't be difficult. But why would anyone want to?

We've been hearing a lot more about the popularity of FKTs and how having a GPS track as proof is important to verify what has been accomplished. Recently Ueli Steck was criticized for not having GPS proof of his record-setting climb of Annapurna. When asked how he felt about the criticisms, his response of 'I don't care' made me smile. He's doing what he loves for the right reasons. Along with high-profile FKTs is a swell of online training sites where pitting our efforts against others has turned training itself into competition.

I don't use Strava. I rarely use a GPS watch. I totally get what Steck said, because I don't care either. I personally prefer my training runs to feel nothing like my work and nothing like a race. That's just me.

I do care about integrity however, and downloaded GPS files are not the proof that a lot of people think they are. Any data that is contained in a downloaded file can simply be overwritten to show something completely different. The files contain a long list of coordinates that make up the route, each with a time stamp. If you change the coordinates, you change the location on the map. If you change the times between points, you change the speed.

If GPS is to be used as a true 'witness', it needs to be via a live tracking service such as SPOT, or the unit should be passed off to a third-party to download and verify the data. Both of these approaches eliminate the opportunity for data tampering. This wouldn't verify the mode of movement or the actual person doing the movement, so it would still need to be augmented with other evidence. In many cases a person's reputation and known ability is the only proof that really matters.

For kicks I just opened a Strava account (noting their motto: Prove It) and uploaded a GPS file of a route (to max out my nefarious ways, I stole it from Derrick). A few minutes later I uploaded the exact same route, but at a significantly faster pace.

Original File showing 5:20 per km pace.

Significantly quicker at 3:34 per km. Look at all those awards!

It's just as easy to change the locations of the points. Here I shifted a run out to the Atlantic Ocean. It could just as easily have been anywhere, over any type of terrain.

4.7 km in the Atlantic
To combine those two manipulations, it is possible to create a partly- or completely- fictitious run from the comfort of your own desk chair.

I'm not saying anyone is actually doing this, but as the sport changes and grows it's good to be aware of what the limitations are to certain types of technologies. When it comes down to it, a person's reputation and integrity are sounding better than ever.