Step counting vs distance

I noticed that some watches do calculate the distance from the steps. Probably just multiplied by the stride length. Shall we add that to the health app? Any opinion on this?

Timely question as I have been thinking about this.

I dont think the watches have stride length set anywhere. I suspect the watches that estimate distance are just using an average stride length value - so they are probably wrong (I could be wrong as I have not checked what they do.)

Stride length can be estimated from height using a formula. See the thread on calories.
https://forum.espruino.com/conversations­/391450/#comment17183506

Calculating stride length from height is more accurate than using an average but
a persons actual stride length may be slightly different from their actual if using one of the measurement methods. I am pretty certain my stride length is a couple of cm longer than what is suggested from my height.

However we really need to agree where certain attributes of personal data will be stored.

Some people have strong preferences on personal data (age, height, weight, male/female).
I was about to post about how this could be done. It could be done using a plug in App a bit like 'My Location' works. That way the settings can be added as a plugin app and if anyone
does not want such personal data stored on their watch then they dont install the app. It could also be part of the Health App.

I will start a seperate thread to discuss this in more general.

Stride length can be estimated from height using a formula.

I'd suggest the user should be able to set the stride length directly. It's not hard to walk a number of steps and measure distance with a long tape measure (walking 5-20 meters should give a good average I think). Or record steps and gps in a recorder log and average the stride length from that.

I would also say to set the stride length instead of height or anything.

I would also guess that health is the only consumer for this so I would not move that to another app yet.

I would guess that GPS is too inaccurate. You would need to walk 100m-1000m to get a good value.

We could set an average stride length as default and everyone that wants to change that can do so in the settings.

We can algo go all the way:

1. Use average stride length if nothing is set
   
2. Calculate stride length from height if only latter is set (thats where the profile app/lib) becomes useful
   
3. Use stride length if set.
   
4. Add the option to set stride length from GPS later
   

Gps is very accurate. Far more accurate than step counting an average stride length. Gps is expensive on power consumption.

Sorry no, unless you use e.g. RTK correction (which we don't) gps error is in the magnitude of tenfold of meters, so you just can't walk 10 meters or even less and expect to be able to calculate a reasonable stride length.

Agree you would need to walk 100-1000 steps to get an accurate distance measurement and then divide it by the number if steps.

My point was tha GPS is far more accurate at measuring distances rather than trying to infer it from a step count. When people walk they walk a mixture of short and long steps. What I am saying is that distance based on step count is flawed as a concept, the error range builds up very quickly - it can only be used as a rough estimate, which is all those watches will give you.