Suunto 9 FusedAlti not remembered after activity

surfboomerang

The track should be flat, but it is slowly corrected to (almost) the right altitude in the end.

freeheeler

@Dimitrios-Kanellopoulos
you mean it still wants to correct, even when paused?

Dimitrios Kanellopoulos

@surfboomerang yes but even if you had the altitude at start at 1000m the same chart could happen.

At start it would calibrate immediately to let’s say 10meters and slowly go to 0. So initial calibration error would be 10meters (just en example)

Also the flat at NL (I have sometimes same charts) is not always so flat (or everywhere).

For example my house is at -10 while at 5km I am at 0 (sea).

However this is going to be improved for those 10meter variations. That line will go correct much faster for flat runs.

10meters is very small error but it shows well if you do not live in a mountains area.

Dimitrios Kanellopoulos

@TELE-HO correct. Also in the prestart screen it will do it. Sometimes even if you just turn on the gps for 1min if it can.

Prestart is when you see the start and wait for the gps lock

freeheeler

@Dimitrios-Kanellopoulos said in Suunto 9 FusedAlti not remembered after activity:

temperature influence

this is temperature influence, alright. I’ve learned something new.
Then we also need to be aware of changes e.g. when we start a hike with a shirt in the cold and put on a warm jacket and gloves that heats up the watch body and sensor, right?

freeheeler

@Dimitrios-Kanellopoulos said in Suunto 9 FusedAlti not remembered after activity:

10meters is very small error but it shows well if you do not live in a mountains area

true! don’t get me wrong, I just want to understand and learn since I observed this behaviour

Dimitrios Kanellopoulos

@TELE-HO temperature will influence more when there is no pressure change or if you are “static”.

No it won’t influence asap.

You should not worry about it at all. It need sharp change.

However, if your sensor is dirty yes it will. Not because of the algo or the component but rather of the debris that will do a systolation or diastolation and move the component (sensor).

freeheeler

@Dimitrios-Kanellopoulos
interesting stuff and nice to know
in general: we shouldn’t worry too much.

Dimitrios Kanellopoulos

@TELE-HO about temp yes. Only if your sensor is bad. In general you should also not worry about a watch and a few meters difference if it works ok mostly. That is a personal advice.

stromdiddily

@Dimitrios-Kanellopoulos Also in the prestart screen it will do it

This is super interesting. So if I wanted to get the best altitude reading I should get to the pre-start screen outside OR at least wait a bit before starting my run?

Usually I will start it inside my home to get a HR lock, then head outside to tie shoes and get on with it.

isazi

@stromdiddily said in Suunto 9 FusedAlti not remembered after activity:

This is super interesting. So if I wanted to get the best altitude reading I should get to the pre-start screen outside OR at least wait a bit before starting my run?

Yes

Dimitrios Kanellopoulos

@stromdiddily explain to me what benefit the <10 meters precision will give you during your activity and I will answer. (Joke but also a bit interesting question for my understanding )

Ok i ll answer: yes you can stay static in open space and it will be better. Be that be in prestart screen ? During a pause ? During the activity ? It doesn’t matter anymore. It will do it perhaps better due to being static and facing the sky not wobbling at the side of your body with a great shadow of your body covering 50% of the horizon.

Fenr1r

@Dimitrios-Kanellopoulos said in Suunto 9 FusedAlti not remembered after activity:

explain to me what benefit the <10 meters precision will give you during your activity … Joke but also a bit interesting question for my understanding

OK, for me, rather than @stromdiddily:

Case 1:
Imagine you are in a place where there are no tracks but identifiable “summits”. A plateau, or moorland, say.
Imagine reliably-surveyed maps have identified and differentiated points of elevation to within that 10m precision. In fact, down to 0.3m precision.
Imagine you do not want to wait for the watch to display your location (and are running another S+ than SAFE) in coordinates and relatively slowly locate yourself on the map that way.
Imagine visibility is this (high summer, 11:15, around 30m to the lumpy silhouette):
Fur B.JPG
And you don’t recognise those particular rocks but know they’re at the top of a hill. Your altitude (and your course) give you your precise location.

If there are different heights, the top of whatever rise you’re on is likely “HIll 632” or whatever. NOT “Hill 633”. The less visually dramatic equivalent of a peak. That is a fast enough location fix that you don’t have to break stride. Your altitude (and your course) give you your precise location.

Case 2:
Following contour lines to bypass a cliff, watercourse or other obstructive feature otherwise obscured from view. With an accurately-surveyed map, the altitude precision saves wasting energy when you need to conserve it.

Dimitrios Kanellopoulos

@Fenr1r why not then just gps position ? What am I missing?

He refers to start position altitude if I understood right.

If we are going to say it’s like a high store building were you walk on a balcony and you need to detect which floor you should be (if I understand correctly ) imo the -±2, 3-10meter error won’t get you so safe. There I would not try to trust my watch to be honest nor any gps based device. But I like the conversation .

Fenr1r

@Dimitrios-Kanellopoulos said in Suunto 9 FusedAlti not remembered after activity:

@Fenr1r why not then just gps position ? What am I missing?

Time.

How many digits do you have to keep in your head to differentiate, say, 3 possible coordinate locations vs 3 max elevations? Think about it. X+Y, and those coordinates only start to vary at the end. Without a map on the watch (where this wouldn’t be a discussion) most people would have to double check those coordinates with the map each time. Having waited for the watch to produce them, or leaving it stuck on “Find Location” screen, providing no other info.

With 3 sites, even working in feet, it’s hard to go beyond 5 digits (each) on Earth. And the watch can still be providing whatever other goodies it can. Possibly just direction. Or time.

There I would not try to trust my watch to be honest nor any gps based device.

You might remember I wanted to include manual input in the Alti Fusion. This is why. (At user risk, of course.) I’m not leaving it up to Skynet.

Dimitrios Kanellopoulos

@Fenr1r ok this make sense. Thanks man.

Fenr1r

@Dimitrios-Kanellopoulos I failed to appreciate your picture before. Fun stuff.

stromdiddily

@Dimitrios-Kanellopoulos said in Suunto 9 FusedAlti not remembered after activity:

@stromdiddily explain to me what benefit the <10 meters precision will give you during your activity and I will answer. (Joke but also a bit interesting question for my understanding )

Haha that’s a damn proper answer