Bad distance measurement when recording hiking

Hm, it looks as if the units got mixed up somehow. Perhaps during the version upgrade. 4.4 km is 2.74 miles. Make sure that units are set equally to metric system on all three platforms (Instinct, GC Mobile, and GC Web). Once checked, shut down and restart Instinct, and then try it again with a short walk.

Edit: Better told, if the units are already set to kilometers in Instinct, change them to miles, restart, then set back to kilometers, and restart again. Perhaps not necessary, but I already saw a similar case with an old Forerunner 45, where toggling the units, and restarting was necessary for making the change effective.

As for the second activity, its privacy settings do not allow me to look at it, and although 13.53 miles is not equal 17.83 km, I still suspect, the units mixup could be involved. I'd need to see it, to verify.

If you set a stride length, then maybe the distance is calculated as

distance = number of steps * stride length

I.e. if the stride length isn't correct, the distance isn't correct.

Try without setting the stride length, then the distance must be calculated from the GPS data.

I do not think the distance is ever calculated from the stride length, when GPS is on, but you may be right that it is perhaps worth of verifying anyway.

Thank you for the answer, I also made the second activity available and will try to restart the device

I was looking at an older activity, when according to garmin it shows 17.6 km and according to gpx 19.57 km - connect.garmin.com/.../4528535598 . I set the length of the step according to the measurement of the watch's instinct. The measured length is divided by the measured number of steps, but perhaps this data from the watch may not be accurate and the data on the length of one step is thus distorted, such as the distance traveled. I will try to set it again

Thanks

Turn off the custom stride length entirely. 

I have looked at the second activity, but the ratio mile/km does not apply in this case, and I did not see anything that would explain the difference  - there is nothing like for example too low pace, or a dropped GPS signal. So, you can try resetting the units, restarting the watch, and disabling the custom stride lenght, and let us know whether it helps. Subra  was perhaps finally right about the stride lenght. Although it sounds foolish, perhaps it indeed overrides the GPS distance, when enabled. I never tested it.

I don't think it is the custom stride length as even when set and enabled on watch and in Garmin Connect mobile and website the watch doesn't use the custom stride length even when GPS is turned off and it should do.

I have tried using the Hike activity without GPS, counting the steps before and after during the activity and each time it has been exactly in line with my custom stride length. 

However the watch seems to ignore that even though it could accurately calculate distance, it instead uses its own stride length calculations and under records distance everytime. 

Concerning GPS, even with 3d distance on, the Garmin Instinct slightly under records distance on a regular basis.

On a 10 mile run the Instinct will underrecord record by anything between 0.05 - 0.15 based on the route plotted. 

I also take my Ambit3 Peak with me, which has the GPS antenna nub and excellent GPS Accuracy. When hiking and running, if I choose 3d distance on both watches the Ambit3 always records a longer distance, sometimes exactly the same as the plotted route and sometimes slightly more which I tend to agree is the real distance when you add in lots of ascents, descents, not running tangents etc. 

Obviously the plotted route is not exact to the actual route ran as I don't run down the middle of the road or path and do not run in diagonals or run to the centre of a junction then hit a hard right angle like routes plotted. 

The underrecording is very slight, often by less than 1% and never more than 2% of the course. Although if you have to run an extra 200 metres it will affect running times. 

It may be that the Instinct is closer to the true route ran then the map plotted or the Ambit 3, but looking at the GPS track after every run/hike tells me it undercuts corners is often offset to one side and further away from the path I took than the Ambit and the plotted route. 

Tom said:

Garmin Instinct slightly under records distance on a regular basis.

It is in fact done in purpose. Most Garmin devices report distances of activities in this way, and it is intentional and with a pupose. If the pace drops under cerrtain threshold (for example under 1hr/km at the Hike or Walk activities), even if you continue slowly moving, the motion is no more considered to be worthy of being applicable for the activity distance, and hence not being included in the total distance. The same happens when the device loses the GPS signal for a moment (that can happen near tall building, in narrow valleys, etc.) - those parts are then also not included in the total distance.

And this was exactly the reason why I asked for the links to the activities, so that I could verify how long parts of the hike were done with a pace under the limit, or without GPS signal. And in these two cases, such sections are completely negligible, accounting together for some 50m only (in the first activity, and similarly negligible in the second case too).

So there is still another problem involved in case of Olda. The first activity looks like the unit system mixup could have been the culprit, but it is not the case at the second one. We'll have to wait for more feedback from Olda, to exclude this possibility, as well as excluding the possibility that the custom stride length infuences the calculation (perhaps due to a bug in the latest firmware version).

I've had a look at your activities and I wonder, why in both is the HR at times down but the pace isn't. 

The difference in distance may be due to GPS drift.

When stopping during a hike or another activity and the watch is not paused, the position error is accumulated continuously to the distance.

Garmin recommends to switch "auto pause" to on.

support.garmin.com/.../

Please have a look at the image "GPS Indoors" to see what is going on.