Komoot inconsistency

[Gringo]

Dose anyone else use Komoot ?
I've been happily using this free app to record my rides fo years and I’ve never question the accuracy of the information recorded, that is until now.
since being in lockdown ( also being furloughed ) I’m riding nearly every day, a longer ebike ride at the weekend but on weekdays I’m riding my analog bike On the exact same journey every time. Recording the trip on komoot to see if I’m improving,
On the first 6 rides there’s been a slight discrepancy in distance and elevation but today for the identical route I’ve lost over a mile and a half and 100 feet less in elevation.
Is this typical of all devices using gps and how can you trust the rest of the information Given.
here is a screenshot of the stats for my last 7 rides

 

[sjpt]

I don't know about Komoot specifically, but most GPS are very inaccurate in elevation. If Komoot relies on GPS elevation and adds together all the ups but ignores the downs it is likely to get an exaggerated idea of total climb, that will also vary for each ride on the same route.

I must check again, but I think ViewRanger will show both GPS recorded elevation and also elevation from map data for the recorded position; at least when reviewing a route even if not in realtime.

 

[GLJoe]

I don't know about Komoot specifically, but most GPS are very inaccurate in elevation.

This.

And I have a feeling some GPS modules are a bit iffy for X,Y coordinate data as well. Especially if they are an inexpensive add on (such as in a phone).
I've often noticed that if I'm recording a route on my GPS cycle computer, and my wife is on the same ride and recording using Komoot on her phone, her distance and elevation recorded is usually a fair bit more than mine.
When I check the route using either google or the Komoot web based planning app, its very close to my dedicated GPS device's results.
So it seems its the GPS accuracy of many phones that's likely to be the problem if you're relying on the recording to give you the actual stats. If those are important to you, probably worth putting the route into a planning app and using that info?

 

[sjpt]

This.

And I have a feeling some GPS modules are a bit iffy for X,Y coordinate data as well. Especially if they are an inexpensive add on (such as in a phone).
I've often noticed that if I'm recording a route on my GPS cycle computer, and my wife is on the same ride and recording using Komoot on her phone, her distance and elevation recorded is usually a fair bit more than mine.
When I check the route using either google or the Komoot web based planning app, its very close to my dedicated GPS device's results.
So it seems its the GPS accuracy of many phones that's likely to be the problem if you're relying on the recording to give you the actual stats. If those are important to you, probably worth putting the route into a planning app and using that info?

Yes. Generally the x/y accuracy is much better, but I often get isolated rogue readings that are way out and really inflate distances if not filtered. I partly chose my current (cheap) phone because it's got relatively good GPS; previous more expensive mid-range LG phone had very poor GPS. Not usually covered in reviews.

 

[GLJoe]

Yes. Generally the x/y accuracy is much better, but I often get isolated rogue readings that are way out and really inflate distances if not filtered.

And to add to the conversation some more ...
I have a hunch that what we are both seeing, is that there is an algorithm in much of the recording software where the x/y data is compared to known routes/paths, and if its out by a small distance, it 'quantizes' or alters the data to match a known route - but only up to a point. If the error is too great, then you get your 'isolated rouge reading' which is actually the usual erroneous reading, just not modified!

I've also noticed that different phones have very different accuracy. And yes. its very annoying that most reviews don't check this!