Option to correct/add track elevations

[St0rml]

Summary

With this feature, tracks with bad elevation data or no elevation data at all can be updated and corrected using e.g. SRTM data. Elevation data is for most activity tracking a quite essential metric, however, cheaper GPS tracking devices often don't support recording it. This feature would reduce the steps users with no elevation data need to take to have a complete/finished track in Wanderer. At the moment, the addition of this data needs to be done in an external application.

Examples

GpxPod

The Nextcloud Application GPXPod uses data by CGIAR - Consortium for Spatial Information. The implementation is done in these files

• Mainly here: SrtmGeotiffElevationService.php
• Using this: SRTMGeoTIFFReader.php

gpxz.io

Another option could be service provided by gpxz.io. They use LIDAR-Data wherever available and SRTM-data otherwise. (see their map on the Dataset site).
They provide a free API (100 requests per day, though they write "For Testing only"). So I could see a feature in Wander, where a user can require their own API key to use this service to correct their tracks. Requests don't need to be made for every point, instead the Raster API could be used to download an 2D extract for the bounding box of the track. More advanced users, or e.g. admins for larger communities, could even host their own Open Topo Data server for virtually unlimited requests.

I'm feeling motivated to look into this feature, however I'm not at all familiar with the technology stack of this application.

[St0rml]

This might be a duplicate of #130, as this has been mentioned there and also in the PR #135
However, it seems like this issue/feature has then not been brought up again (on github).

[Flomp]

Hi,

This is indeed a recurring suggestion, but an important one nonetheless. I would like to avoid having yet another dependency in wanderer, which is why I would like to use valhallas elevation endpoint to achieve this. We already use it fetch the elevation data when the user draws a route. It should actually not be to difficult to also do this when the user uploads an existing track.

I'll have a look at it.

[rogertheriault]

Howdy. I have been trying Wanderer (❤️ love it!) and noticed the elevation info for the hikes I uploaded appeared to be zeroing out or quite low compared to what my watch showed, and compared to what I actually experienced. Maybe I need to RTFM but I saw this and thought I'd chime in.

I agree the numbers used for smoothing may be a bit high. If it's not possible to provide adjustments or settings yet, perhaps lower them, but an override via config might be a start.

Since I saw a comment in #135 about not having good samples, here's one. Too big for pastebin. It's from Apple Watch, with one position per second. It includes some lingering at the top of the hill, a lot of relatively flat slogging, some ups and downs, and a steep climb.

https://drive.google.com/file/d/1Bf1rqxuk_cyMngz1q8kTJe20ghJDcui7/view?usp=drive_link

With the recent versions, my upload shows no elevation gain, and while I am no climber, this was one of my group's toughest elevation gain hikes recently. Elevation gain is an important thing for us, more = more difficult! I'm happy to share more sample tracks.

Modifying the constructor params to 1 and 1 yield a more realistic result, but my Fitness workout says it was 538m of elevation (Apple only shows UP, not down, for hikes. As a former skier, I can see the use for down).

const metrics = new GpxMetricsComputation(1, 1);

Perhaps the smoothing needs to take into account the time deltas (which are in my track, but may not be in other folks' tracks).

Also, speaking of time, if there's not a feature request to "smooth out" loitering time, for example, at the top of that 720m hill we stopped for some beers, but technically that's an optional activity... it might be worth flagging the "loitering" and suggesting it be erased / smoothed into a single point, subtracted from duration (or moved to an idle vs active statistic), and a waypoint created. I've also got lots of tracks where we stopped at a waterfall for a bit of swimming, and returned the same route. We return to our starting point almost every time, and I think that's why the elevation numbers have been very low.

I'm really liking this app, great work, thanks!