Elevation starts at zero?

Joshville

I have my Adventurer set to automatically export to Strava. I'm not sure if this is really their problem or if it's something TomTom should do differently... It seems like the very first entry that the Adventurer creates in the .gpx file for an activity is at zero elevation. MySports seems to ignore this outlier and report elevation gain correctly. However, Strava honors this zero entry (at least the last few days) and counts starting elevation as elevation gained. Anyone else with this issue? I don't want to have to manually edit every activity...

tfarabaugh

TomTom calibrates to GPS elevation in the first few minutes of the activity and then uses the altimeter thereafter, so in the first second before it calibrates it will show zero. It is odd that Strava is using that as they generally ignore the TT values and do their own analysis using their own Digital Elevation Model based on the GPS points collected. I am not sure which side is doing it right but it is highly unlikely TT is going to take the time and effort to change their system to match Strava. I think you may just have to live with it.

I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.

Joshville

Actually, Strava is trying to build a new Elevation database using community altimeter data:

https://support.strava.com/hc/en-us/articles/115000024864-Announcing-Strava-s-Elevation-Basemap

Due to the spurious zero that TT is sending, I have to specifically tell Strava to use their database instead of my altimeter. Or I'll have to edit the .gpx file and do a manual import every time.

IF this is due to the altimeter not being ready, should there not be an indicator similar to the "GPS Acquired" indicator to say that the altimeter is also ready? The watch shouldn't say "I'm ready" when it's not...

Also, I find it hard to believe that it's an issue of not being ready. Granted, I only looked at 3 gpx exports from MySports, but all 3 of them had only the first entry with zero altitude. The very next entry just one second later reports the correct altitude. This isn't an issue of "matching Strava" so much as an issue of outputting bad data.

PatrickS255

I have the same issue, this morning for the first time, before that not in a year. Suppose it is a change on Strava’s side that is causing this.

Joshville

I figured out that it's not too hard to fix. After the activity auto-uploads to Strava, all you have to do is open the activity in Strava, click the wrench and then hit "Crop". Then just hit the button once to move the start point by a single entry to remove the data point with zero elevation. Could be better (no excuse for TomTom to export that single zero), but not as bad as having to turn off the auto-upload and then manually edit the .gpx file.