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Tuesday, October 18, 2016

Navigation and Trip Statistics

The Garmin Vivoactive survived the Tour of the Alps with flying colors, as expected (see original Long Term review). Pengtoh also brought along the newest version, the Garmin Vivoactive HR, which includes a HRM mounted on the underside. Since we both uploaded our tracks to Strava, we got a chance to compare the accuracy of the two devices side by side.

The most important difference is that the Garmin Vivoactive HR has a real barometer. That means that it gets real altitude/elevation data. For instance, on the Grimsel and Furka day, my Vivoactive got an optimistic 8031', while Pengtoh's Vivoactive HR got a much more realistic 6850'. The most accurate device was probably Arturo's Garmin 810, which gave us 6969'. The Edge 810 is probably more accurate because it has a temperature sensor, which is essential to giving an accurate air density measurement as the day warms up. Arturo's 810 died in the middle of the tour from water damage, however.

Garmin provides a temperature sensor for its watches. The $24 question is: does the Vivoactive HR use that to adjust the air density measurements in order to get more accurate elevation data? The main reason not to have a temperature sensor on the watch proper is that your body heat would heat up the sensor, granting in accurate temperature readings, which would invalidate any results from such computation. Garmin doesn't say and doesn't publish technical explanations for altitude/elevation measurements.

Suffice to say that with the addition of a barometric measurement, the Vivoactive HR is now high on my list of devices to upgrade to before the next tour of Alps. Pengtoh says that the HR function works well even for cycling for him, which is another big benefit.

The limited battery life of the Vivoactive was such that I had to carry an external battery to charge it mid-day (usually at lunch), but the Vivoactive HR that Pengtoh had is good for 16 hour stretches with the GPS turned on, which eliminates even that weakness.

By the way, one of the most hilarious aspects about the Tour of the Alps is that the Vivoactive is clearly designed for sedentary people who don't do massive bike rides. It was funny during the tour to look at the watch and see it register 4000-5000 calories a day (a massive under-estimate, by the way, since the Vivoactive doesn't know that my bike was carrying a touring load), while the Garmin Connect app's "Insight" feature kept telling me that I was being less active than usual, while the Garmin "Auto Goal" feature kept telling me that I'd missed my "step goal" for the day. The poor Vivoactive kept scaling down its "step goals" and missing them during the entire tour.

Given all that, the need for a dedicated cycle computer is no longer apparent except for the navigation features. In rural country towns and alpine country with few roads, the Garmin Edge 800 performs admirably. However, Google Maps has also improved to the point where in urban areas or places with dense road networks it's actually more useful. The smart phone touch screen interface is also better than the Garmin maps screen. It's strange that Google Map's cycling directions are sporadic --- we had availability in Switzerland, no availability in Italy, and full coverage in Austria and Germany. But in any case, when it was available, the provision of elevation changes en-route means it's a much better source of information than Garmin's offering.

As such, for future trips, a Vivoactive HR (or whatever replacement model available at that time) coupled with a waterproof phone (with an international data plan!) capable of Google maps and a bike mount for the said phone potentially the better touring solution. You'll always need paper maps for large scale coverage and designation of scenic routes which Google will probably never provide, but you've always needed them anyway. This is a huge change from previous years, where the lack of international data plans and incompleteness in offerings from Google Maps made such use of phone navigation lacking.

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