stride, recorded activity distances and step distances (some noob questions)

It does use GPS distance for outdoor runs. But the bends on athletics tracks create accuracy problems. However, there is a specific Track Run mode for athletics tracks, which normally produces a pretty good result once properly calibrated. https://support.garmin.com/en-US/?faq=eH8V1VwjN338uo8C5PgDJ7

Treadmill runs will use stride length.

what a helpful response. Many thanks.

I was only using the running track to measure my stride length. EDIT: i'm particularly grateful though for your link to track run - i didn't even know this app existed. Tyvm.

So basically any GPS tracked activity will use that for distance?

And certain other activities (i did think about stationary / treadmill running as a possible scenario where stride length would have to be used) will use either the garmin stride length or a custom one?

- gps can be accurate but is highly variable based on several factors

- an accelerometer in the watch is also used to augment GPS but i wouldn't worry overly about that.

- i would expect +/-0.5% distance accuracy overall but with high variability.

- cadence/strides are worked out from the onboard accelerometer and sometimes a chest strap. assume they are correct

- there is a stride length data fields IIRC. that is a simple calc based on GPS distance.

- you should have a TRACK RUNNING mode. use that. it should be more accurate

-  i don't understand your height comments nor if your reference to stride means the STRYD footpod. if you are talking about STRYD the answers to the above are different and you might want to ask STRYD directly.

thanks very much for the reply and helpful content.

"i don't understand your height comments nor if your reference to stride means the STRYD footpod. if you are talking about STRYD the answers to the above are different and you might want to ask STRYD directly."

I read that garmin assumes a stride length, derived from one's height. "The height you have listed under your user profile is used to estimate your stride length and thus will estimate the distance you have traveled." (https://support.garmin.com/en-GB/?faq=ky5UNByyYh9iXay7mvbnt9)

In my short 400m step tests, my watch was accurate to within 1-3 steps (assuming i counted correctly myself!).

I'd not encountered a foot pod or STRYD until you mentioned it, so no, i wasn't referring to it.

Thanks.

The example quote you gave didn't address my original questions.

I guess my questions were fundamentally to do with how distance is calculated and how stride length, which is estimated in some situations, might impact on distance accuracy (if GPS isn't being used).

Also, due to long term knee damage, i can't really run now. I don't use my garmin for running analysis or to better my technique. I, until very recently, used the run app to track usage and distance in field hockey training, the odd 5k, etc. So, basically, i don't use the in depth running metrics available on my watch.

Does this make things clearer?

regards,

Gary

One thing I know for sure that the distance reported by my Fenix 6X is regularly shorter than its own GPS distance. In other words, when I export FIT in many of 3rd party apps that analyze the reported track and connect all trackpoints or, for example, do distance correction in Strava, distance often increases by 3-5% percent. That applies mostly to trail running activities, and on activities with open sky and straight tracks distance discrepancy is minimal. 

Given GPS plots have a CEP of about 5 meters (including behind you), summing the distance between each individual track point is unlikely to give you an accurate total distance covered.

One thing I know for sure is that mapping is hard, really hard. I don't pretend to understand them myself, I just know that the complexities are significant, and not always obvious.

These GPS plots are heavily filtered and interpolated even before they are saved to device storage. How else would you explain cutting heavily into corners? For sure, Fenix doesn't produce each trackpoint individually, otherwise it would be a complete mess.

silentvoyager said:

These GPS plots are heavily filtered and interpolated even before they are saved to device storage. How else would you explain cutting heavily into corners? For sure, Fenix doesn't produce each trackpoint individually, otherwise it would be a complete mess.

On the contrary, I believe my fenix 6xPro does indeed "produce" and record each trackpoint individually.  I have my GPS Data Recording set to record Every Second.  Here is a portion of a Walking activity I did recently exported to Google Earth - notice each trackpoint (the yellow circles) appear every second, and no "cutting heavily into corners" is evident:

Note: I was walking at about 19:44 min/mile on the left side of the street - looks like very little fitering or interpolation to me.

Perhaps you have Data Recording set to Smart or even UltraTrac and are not recording every data point?

HTH

Edit to add:

Here's what that part of the activity looks like in Garmin Connect:

It's satisfying to see a good correlation between the map/track in Connect and the map/track in Google Earth.