2013-05-06

Strava bringeth bad news

I'm in the bay area right now, and the new owner of a Google Nexus phone, which is very good at integrating with Google apps, including calendar, contacts and mail. It also runs Strava, the defacto standard app for logging your cycling, then uploading the results to compare with others. I'm assuming its running Hadoop at the back end, given their Platform Product Manager is one of the ex-Yahoo! Hadoop team.

If this is the case, Hadoop is indirectly bringing me bad news.

Yesterday I went out on the folding bike and climbed the Santa Cruz mountains, west of the Bay Area flatlands.
Old la honda map segment
It's a great steep climb from behind Palo Alto up to the skyline ridge, narrow and free from almost all traffic bar the many other locals who felt that Saturday morning was to nice to waste. For me: 26 minutes climbing, 40s of rest -fast enough to come in the top 50% of the day of everyone else running the app, and hence 2233 of 5810 of everyone who has ever done it. Not bad work.

Good news from strava: 62/145 on Old La Honda
If there's a warning sign, it is that people faster than me have a quoted average power output less then my 257W -and as they all took less time, that means that their total exertion is less than my 412kJ. Why do those ahead of me come in lower? It means they are carrying less excess weight.

If I'd stopped there and descended (carefully, that bikes 20" rims overheat), I could get back and feel relatively smug.

Only this time I descended the far side and climbed back up "Alpine West" -first time ever. And it destroyed me
Bad news from strava: 28/29 on west alpine
It was long. I stopped for lunch partway up, but needed that rest, and continued, expecting the overall climb to be on a par with the earlier one. It wasn't. In fact the total climb was double, 600m. Which I was not ready for. Unlike the morning, where I'd got to pass lots of people, there the road was near empty -and those people I did meet were going past me. The rate of ascent, 562m, is less than the 600m/hour rate we used to plan for when crossing the alps -a rate sustained over a week or more, carrying panniers. Not today.

The message from Strava then, which means something Hadoop worked out, is that I am overweight and completely lacking in endurance. It' doesn't quite spell it out, but the graphs bring the message

This is datamining at work.

2 comments:

  1. Whether or not you can achieve 600m ascent per hour surely depends somewhat on the gradient? Anyway, how much fun did you have? No amount of data mining will ever tell you that...

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  2. @matt: actually that 600m/hour used to be gradient-independent: gentler slope, we'd go faster. My little altimeter watch was the best estimator of time on climb remaining. That is, unless you think the height of a pass is 300-1000 metres lower than it turns out to be, which has caught us on both Petit St Bernard and Timmelsjoch.

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