Pace Graph is not a smooth graph

What type of activity is it? A walk? Outdoors or indoors? Did you walk continuously without stopping? Did the steps counter continue incrementing? If an outdoor walk, was GPS on, and locked? How does the map look?

Hi.  It was a SUP activity, and I was paddling in an outrigger canoe at a very slow stroke rate maintaining zone 3 heart rate.  I have never had this issue with either my Forerunner 910xt or my Vivoactive 3 watches.  Everyone I know doing the same activity is not experiencing this.  I'm just trying to understand what is causing this?  See map.

See similar activity just days ago

Compared to the problematic graph below:

And does it happen at a faster pace too? If you do small pauses in the paddling, the watch may interpret the lack of arm movement as a pause, and drop the pace to the "stopped" value of 1hr. Either try going faster, or paddling shorter strokes without interruptions.

Sorry.  That's ridiculous. See the two graphs above.

From the graphs I cannot see how frequent your strokes were. And I also do not know whether you used the same firmware version. It is possible that the cadence threshold changed in the recent version. Make some tests with different cadence and pace, and you will see whether you can exclude that possibility. Sorry, other than that, I cannot offer you any better explanation. Contact the Support for a better answer.

Thanks for offering insight.  My spm was averaging in the 40s.  If I change the graph from Pace to Speed, the 'drops' correlate to 0.0 mph which is not the case.  For every stroke the canoe is gliding and not coming to a complete stop.  Plus...nobody else doing the same activity im doing is seeing this phenomenon.  The two graphs i shared above are two different days, same watch, same software version. 

5041308 said:

For every stroke the canoe is gliding and not coming to a complete stop.

The speed is not always derived from the GPS coordinates. Accelerometer data is used too, and under certain conditions it overrides the speed calculated from the timestamps and the GPS coordinates. This is done in order to avoid recording false speed and distance values in case of low GPS accuracy and to eliminate the effect of the GPS drift. So for example the speed & distance values will override the GPS values when the accelerometer does not detect any strokes (or steps in case of walk and run activities), because it guesses no motion, and therefor attributes the change of GPS coordinates to the GPS drift. The accelerometer cannot detect the gliding, it can only detect the strokes.

I do not use the SUP activity, but it works in this way at activities like Run, Walking, or Hiking, so it is likely used at SUP too.

5041308 said:

The two graphs i shared above are two different days, same watch, same software version. 

Perhaps the GPS conditions were not the same, or your CPE (ephemeris data) file was expired or corrupted at the later activity, or the cadence was not the same. If you share links to the activities, I could perhaps spot some difference, or find the culprit in the hidden JSON data.

There is also some calibration involved in the use of the pace & distance from the accelerometer. So that could be another reason for the difference between the two activities. If the stroke/pace calibration factor got lost, or was overridden with wrong data, it would cause differences in the graph too. You can try hard resetting the watch (pressing the Light button for some 20s till it shuts down, and then restarting. No data or setting is lost). If it does not help, the master reset to factory defaults should reset the calibration.

Avoid recording false speed?  That's exactly what it's doing! LOL.  I appreciate all that said about the accelerometer and gps, but that's not what is causing the issue.  And if it was, that's just lame engineering. Like I said, my 910xt nor my Vivo3 has this issue.  Neither do others doing the same activity.

I also don't sus the script since I confirmed by monitoring the speed and looking at my watch between strokes and noted it actually does say 0.0 mph.

So...i did a test today.  I seriously thought it was some kind of battery saving mode since it was down to less than 20%?  So I charged it overnight. But then thought...that's just lame engineering again.  What I also did differently was I did a Satellite Acquisition before starting the activity.  However, I always thought the GPS acquisition always happens when you start the activity!  Anyway....this was the result.

I'll continue testing...but im at least relieved that the 'anomaly' isn't consistent.  I can live with human error LOL

5041308 said:

What I also did differently was I did a Satellite Acquisition before starting the activity.  However, I always thought the GPS acquisition always happens when you start the activity!  Anyway....this was the result.

There’s the most likely reason. You’ll see in the user manual that you must always ensure you have acquired satellites before pressing start. There are some who also recommend waiting a minute or two longer after the satellite connection is confirmed. Once you get moving the watch is looking to get a good connection but struggles or even fails because the ‘targets’ are always moving. I usually select my activity while I am finishing my preparations before starting whatever I’m going to be doing. In practice this means my watch will be hooked up to the satellite some minutes before I press start so had plenty of time to settle.