Activity info.elapsedDistance has unexpected jumps

Has anyone noticed abnormal jumps of data reported by Activity info.elapsedDistance. The value seems to jump by about twice the expected rate once every 22-23 secs. This occurs both when reading a FIT file and also when having the simulator simulate data.

The attachment contains a CSV file showing a log of elapsedDistance (from a recorded FIT file) as reported by the SDK (ver 1.2.9) and highlights the data jumps. THe data was captured in ideal conditions, full GPS coverage etc.

jim_m_58 over 9 years ago

If you playback a .fit file in the sim that was recorded with "Smart recording", the jumps are normal, as the data isn't saved on a constant basis (saved when needed), and therefore it's not fed back at a constant rate. (you'll see this based on the watch used to record the data)

"simulated data" should be every second though, but it's odd in a different way. It's a 2 min repeating loop. It heads south for a bit, then angles North East. Then it jumps back to start with no data during the "jump", and I'm not sure if it was based running speed or driving in a car :).

Jan Čapek over 6 years ago

One user of my Ebike Field - Nerd Style send me REALLY strange behaviour of info.elapsedDistance . He had Fenix 5S Plus with FW 7.10.

Please check short video. On first screen there is ebike field with distance fluctuating on left-down corner of the screen next to stopwatch while on second screen is native distance field. The datafield reads distance from activity quite straight forward so I was quite surprised by it:

function compute(info) {
    if(info has :elapsedDistance){
        distance = info.elapsedDistance;
        
        ....
    }
}

function onUpdate(dc) {
        // distance
        var distanceLocal = "0.0";
        var distanceUnit;
        if(mySettings.distanceUnits == Sys.UNIT_STATUTE) {
        	distanceUnit = "mi";
        	if ( distance != null ) {
        		distance = distance * 1.609344;
        	}
        } else {
        	distanceUnit = "km";
        }
        if(distance != null){
           if (distance >= 10000) {
            	distanceLocal = distance / 1000;
            	distanceLocal = distanceLocal.format("%.1f");
           } else {
              	distanceLocal = distance / 1000;
            	distanceLocal = distanceLocal.format("%.2f");
           } 
        }
        
        dc.drawText((sc?87:79), (sc?165:150), Gfx.FONT_SYSTEM_MEDIUM, distanceLocal, Gfx.TEXT_JUSTIFY_RIGHT); 
       	dc.drawText((sc?88:80), (sc?171:157), Gfx.FONT_SYSTEM_XTINY, distanceUnit, Gfx.TEXT_JUSTIFY_LEFT);	
       	
       	.....
       	
}

Is there bug in this particular firmware? No other user reported something like this. This was reported 2 months ago to me.