… without having constant data connection?

Is that a possibility?

You mean an inclinometer? It doesn’t need a GPS and that’s as “live” as it gets.

Does your phone have a altimeter?

https://play.google.com/store/apps/details?id=com.exatools.altimeter

Morning !

Thanks,
What I’m after (not actually for my use, but still) is a function to make the phone act like a (Garmin, say) GPS bike computer – simultaneous and continuous ground speed and current gradient are what’s really wanted

(iphone, I believe)

As scotroutes mentioned, would this not do?

Wahoo fitness will do that.

I know newer Garmin watches and bike computers offer this feature, not sure if phones will though.

if iPhone can you not toggle over to the compass app and swipe over to access the spirit level?

Some Garmins (recreational models with a barometer) will show rate of ascent/descent. Useful for gliders, skiers, mountaineers. There might be some sort of app for that but how many phones have a barometer?

I was under the impression that GPS isn’t brilliant for altitude / altitude change, which seems reasonable(ish) when you think about how it works?

Which is why you’d want a barometer

There might be some sort of app for that but how many phones have a barometer?

iphones have had one since the 6 i think. no idea about samsung etc.