Altimeter watch accuracy

slovhike

slovhike

Thru Hiker
Hi,

I recently bouth a "tank" watch Suunto Traverse Alpha with altimeter function.
Have used altimeter mode yesterday, calibrated height at starting point, climbed a local hill to check the reading
which was -20m off at the top (961m vs. 941m on display). Should there be any tolerance and how much is tolerable to be just accurate?

If this has been covered elsewhere I am sorry for double post and happy to follow any links to old threads.

Regards
 
Foxster

Foxster

Section Hiker
For a wrist-mounted device I'd say that's pretty accurate.

I mean, what difference does it make? It wouldn't affect any outdoors decisions I'd make.

The height is tricky for a watch to calculate as it uses changes in air pressure to determine your change in altitude. This is going to be subject to changes in weather, how accurate the starting calibration was, temperature change, etc. It doesn't use GPS for this.
 
tom

tom

Thru Hiker
Up to 50mt variation (mostly checked on summits or high passes between 2000mt and 3500mt) with my cousin's watch...
 
T

turkeyphant

Section Hiker
Unless you're using a specialised instrument (e.g. a vario) altitude measurements are either awful if they are GPS only or a bit crap if barometric. I'd expect slightly better than +/- 20m but it's not too far off.
 
T

turkeyphant

Section Hiker
Rog Tallbloke said:
A GPS capable smartphone with a mapping app is a lot cheaper than a Vario. Simply read your altitude off the map.
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I wasn't suggesting it, just saying most non specialised instruments are bad at altitude even if very accurate for 2d coordinates. I'm not really sure when accurate altitude is vital while hiking but, as you say, there are easy workarounds...
 
Rog Tallbloke

Rog Tallbloke

Thru Hiker
turkeyphant said:
I wasn't suggesting it, just saying most non specialised instruments are bad at altitude even if very accurate for 2d coordinates. I'm not really sure when accurate altitude is vital while hiking but, as you say, there are easy workarounds...
Click to expand...
I appreciate people want their gadgets to work accurately, but I can't think of many situations where I'd be wearing an altimeter watch and not have GPS mapping with me as well.
 
SteG

SteG

Thru Hiker
I like keeping my phone in my bag and just using map, compass and altimeter. Watch is handy for combining altitude and timing. I find using my phone difficult to use sometimes in winter, sometimes having take my bulky gloves off and getting cold hands, phone starts playing up, ect. Phones are great, theyve helped me out of tricky situations in the past, but find using map, compass and altimeter much more engaging and enjoyable.
 
SteG

SteG

Thru Hiker
@Foxster [ I mean, what difference does it make? It wouldn't affect any outdoors decisions I'd make.]

Good to be able to place your self on the map accurately if you want to follow contours to avoid hazards in poor visibility?
 
tom

tom

Thru Hiker
My cousin is an alpine mountain guide and I can see how for her, a quick glance at approximate altitude and time of day can be very useful when she is out on multi day hikes with a group and particularly away from her local area. And I expect there will be other good uses too. For navigation - probably not...
 
OwenM

OwenM

Thru Hiker
Not hiking but skiing, the Ski Haute route has a couple of places where you have to traverse below an icefall and another where you have to go onto the moraine above another icefall. These are on the Mt. Durand Glacier which is a notoriously foggy place. Having an altimeter was very handy that day.
 
T

turkeyphant

Section Hiker
SteG said:
@Foxster [ I mean, what difference does it make? It wouldn't affect any outdoors decisions I'd make.]

Good to be able to place your self on the map accurately if you want to follow contours to avoid hazards in poor visibility?
Click to expand...
In that case you have 2D GPS accurate to less than 50cm.

tom said:
My cousin is an alpine mountain guide and I can see how for her, a quick glance at approximate altitude and time of day can be very useful when she is out on multi day hikes with a group and particularly away from her local area. And I expect there will be other good uses too. For navigation - probably not...
Click to expand...

Is +/- 10m error going to be non-negligible?
 
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tom

tom

Thru Hiker
turkeyphant said:
Is +/- 10m error going to be non-negligible?
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Its not about accurracy but relevance IMO. I cannot recall a single situation when altitute (without GPS location on map) would have been useful to naivigate. I never saw much use for those little gamin gagets either (following GPS directions on its own is what got people to drive into rivers ("but my GPS said so"). IMO, GPS is only useful in context - i.e. on map where I can zoom in and out to look for landmarks or alternative routes etc. My cousin's watch use is primarily to manage group safety (monitoring stamina etc) and answering silly questions like "how much further do we have to climb?" 10mt or 50mt +/- don't matter much then.

For some people (who don't hate digital watch displays as I do), a quick curiosity check for altitude might be useful or fun. So I'm not dissing these things, just questiong their usefulness for navigation purposes ...:)
 
Whiteburn

Whiteburn

Thru Hiker
tom said:
For some people (who don't hate digital watch displays as I do), a quick curiosity check for altitude might be useful or fun. So I'm not dissing these things, just questiong their usefulness for navigation purposes ...:)
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I find the altimeter a useful navigation tool in certain scenarios as it provides another frame of reference.
Yes, pulling out the smart phone, waiting for a GPS lock then seeing on a mapping app exactly where you are is pretty definitive but time consuming & can be a PITA in the rain. Most of us chose to wear a watch, a very useful gadget for telling the time & timing navigation legs cross-country, but it could be said the phone does that also. Why a watch because a quick glance at the wrist is far more convenient, the same logic applies for myself having a small Suunto wrist compass on the watch band.
Apart from the altimeter aiding motivation on a long climb to a col I’ve experienced a few low vis scenarios where my altimeter has come in quite useful:
  • Traversing open country ‘bump to bump’ on compass bearings, a quick glance at the wrist confirmed I was on the target bump.
  • Descending a mountain side & then using altitude to change navigation ‘legs’ part way down.
  • To simply identify a path junction/ turning at a specific altitude.
  • Contouring around a hill cross country is also made easier, reduces inadvertent wandering.
None of these are particularly overwhelming drivers for purchasing an altimeter IMO but I now value the tool.
 
T

turkeyphant

Section Hiker
tom said:
Its not about accurracy but relevance IMO
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That was my point!

At the same time I acknowledged there are times when it can be useful (eg those mentioned by StegG and your cousin) and was merely pointing out that negligible inaccuracies don't prevent you using it as a data point in that way.
 
KVerb

KVerb

Ultralighter
Woops sorry for reviving an age old buried thread, but I stumbled upon it doing some research on the utility of a watch altimeter.
I'm thinking that the inaccuracies can be useful data in their own right: while using the combination of map+compass+altimeter to navigate, every once in a while you'll come to a spot where the real altitude is exactly known from the map (peak, saddle, ...). If your barometric altimeter is suddenly off by tens of meters, it means there was a rapid change in barometric pressure. If the measured altitude is greater than the real altitude, pressure is dropping so weather is worsening and vice-versa.
 
Patrick

Patrick

Ultralighter
Bit of a thread hijack, but does anyone know of an altimeter watch which isn't also a big, chunky, battery guzzling GPS enabled device? I've been trying to do more "low tech" nav with map and compass recently, partly to be sure I'd still be confident with it if my GPS failed, and its very satisfying. I can absolutely see an altimeter adding to that, but it rather defeats the point if its only available as part of an all-singing all-dancing GPS enabled device - I want to have it as a "low tech" option for when I don't have GPS?!
 
OwenM

OwenM

Thru Hiker
Jakey said:
Suunto Vector or Core , those are what I used to use in my alpine mountaineering days.
Click to expand...
Plus one for Suunto.

You should update your altimeter when you're at a point of known height. If the stated height is going down each time the pressure is going up and vice-verser.
 
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KVerb

KVerb

Ultralighter
I bought a secondhand Suunto Core off of someone here and it still serves me well. The standard strap fatigued and ripped so and I replaced it with a nylon webbing strap off ali to which I attach a Suunto Clipper (tipped by another user on here) for quick bearing checks.
 
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