[S9] Altitude starting at 0

Ashish Nautiyal

@Dimitrios-Kanellopoulos Ohk, so strava basically calculated the elevation gain there. Thanks for making some things clear to me. I still thing its odd to go through this lengthy process to find actual elevation gain, but i appreciate your help

johann.fuehrer

@Dimitrios-Kanellopoulos the ±7m may come from the 15m radius of GPS accuracy perhaps ( i.e. https://lembergsolutions.com/blog/gps-accuracy-complete-guide-dummies ) but I remeber that vertically the accuracy is worse ( you see more satellites BESIDES your position than ABOVE your position and steeper angles to the source multiply the error, or something like that)…

Edit: I have to explain it better: for having a great HORIZONTAL position determined, the best thing would be to have the GPS satellites on the same horizontal plane you are, but somewhere spread around your positon in all directions (north, south, east, west…).
For a great VERTICAL position, as many satellites as possible direct above your position (this wont ever happen )would get the best to get the most accurate height (waighted average of all satellites).

Dimitrios Kanellopoulos

@Ashish-Nautiyal yeah let me also give you more info np.

So here is how it goes:

your watch altitude profile most probably and most of the times should be ok. It can get funky the worse the conditions get. GPS altitude is basically based on ping times afaik.
Once you have the data you can calculate ascent with several ways, add filters and so on.
That value is supported into .fit fomat mostly and some services even override that when you sync and do their own magic. Of course, if that is missing the service should calculate it anyway. That applies for eg to Strava as Movescount does not export the ascent/descent values.
Several services allow you to recalculate the ascent/descent and more data from the “data”, that the fit file contains.

To be honest, it would be great if SA allowed you to do that. Like strava does.
Or allow the user to set the filter.

I hope it helps.

Dimitrios Kanellopoulos

BTW perhaps this plays a factor. The GPS system. GLONASS on/off.

Dimitrios Kanellopoulos

or anything new coming hopefully