February 08, 2006

Skiing with a Garmin ETrex Vista C (review)

As I mentioned on my technical blog a while ago, I got a Garmin eTrex Vista C handheld GPS as a Christmas present. I used this every day on the trip to Megève and it worked very well.

The main functionality that was interesting from a ski perspective was the ability to save the tracks of where we'd been all day and the transfer them to a PC to overlay on the Garmin maps or on Google Earth, etc. It's quite nice to see the scribbled lines of (a rough approximation of) your ski tracks on the map and realise just how far (or not) you've travelled!

Next on the list of interesting features was the altitude profile display. The eTrex Vista C can record your position in 3d using a mixture of GPS altitude and barometric pressure. The result is that your tracks include an altitude component and the device can graph this separately to show your runs. This is similar, but better, than the display that you get from the Suunto S6's software.

Finally there's the trip computer. A display that shows you the mileage covered and the max speed and other geeky data. You have to take the max speed with a pinch of salt (as I discovered when one small section of the track reported a speed of 149mph! Sometimes I ski fast, but, come on!)

All in all, the device was much easier to use than the Suunto S6. It doesn't have all of the timing functionality of the watch but for tracking your skiing it seems more natural (and useful) to use a GPS that can record your tracks as well as the ascent and descent speed. The Suunto has the advantage in that it's specifically for skiing; it splits the lift and ski times and distances where the Garmin doesn't but the Garmin can get an altitude fix from the satelites automatically and therefore you never have the problem of forgetting to calibrate the barometer before the first run as you do with the S6.

Before the trip, I was expecting that I'd need to mount the GPS somewhere obvious (visions of another Princess Leia rig or at least a chest mount with it clipped to my rucksack or something) but it worked fine in my jacket pocket. I switched to 2300mAh lithium cells after it chewed through some Duracells in short order and managed to get one to two days out of a single charge, which is pretty good. The device is small enough and light enough that you can carry it all the time and the lanyard is long enough that you can clip it to you so that you dont risk losing it. The buttons could be a bit small for gloved hands but there's really no need to adjust anything once you're moving.

Be warned that saving a track on the device appears to reduce the accuracy (ie number of points). The 'active log' may contain 1000s of points (you can configure how much memory it can use) but if you decide to save the morning's runs to a saved track then the track appears to be limited to 500 points; you get the whole track shape but at less detail. This may just be a case of me not reading the manual.

Collection of the data on the PC is easy and the supplied Garmin software allows you to display the tracks within it or display them using Google Earth; which is interesting. I have a coding project in mind to collect the data directly from the device and process it in a more skier friendly manner (split out the lift time and automatically identify lifts and runs from your tracks by cross referencing with a set of known data...). I'd also like to crack the proprietary map and routing protocols so that I could download lift, restaurant and ski run information to the device but that's a more complex project.

Of course the one day that I didn't have the GPS with me was the day we did the helicopter trip around Mont Blanc...


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Posted by Len at February 8, 2006 07:55 AM | Categories: Gear
Comments

Seems that Suunto now do a GPS enabled watch (http://www.gpsgazette.com/suunto-x9i-review/reviews/. The "review" is a bit sparse on actual detail and it doesn't appear to be a ski specific device but it looks like an interesting toy...

Thanks to Daz for the pointer to gpsgazette...

Posted by: Len at February 8, 2006 10:34 PM
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