Originally Posted by
Seattle Forrest
I don't really use Strava, in Garmin you can make the X axis time or distance, but that's not what I mean. What I mean is this. You have more data points in your file than you have pixels on the X axis on that chart. Each pixel in the chart represents some amount of time, it might just be the highest or lowest value. My suspicion as a developer who fixes bugs for a living is that the average speed shown next to the chart comes from the Y values and they're being summarized incorrectly. I don't have a way to test that hunch, but in terms of how software is put together, it feels pretty likely.
(Yes, I know I'm beating a dead horse, etc.)
One complication is that the numbers to the side of the plot always faithfully record the same maximum speed as the maximum speed in the summary. They are never smoothed or filtered out. AND, if one looks carefully at the trace of pixels in the plots, those maximum speeds are rarely and possibly never actually plotted. The plotted speeds are indeed filtered. But the values of Max and Avg that appear to the left of the plot don't seem to come from the plots themselve.