Originally Posted by
Seattle Forrest
I wouldn't be surprised if the top number came from the data of the file, and the average you see next to the speed chart was the average of the values in the chart. You would expect that to be the same thing, but there may be some smoothing, ignoring of zeros, or summarization that happens before the numbers are converted into a graph.
If the x-axis is distance, rather than time, the graphically "averaged" velocity is nonsense. You know that. It's possible that the algorithm calculates a graphical average with elapsed moving time as the independent variable, And then maybe smoothing could introduce a difference, though I don't see why that difference would be systematic as compared to the mathematically rigorous quotient (total accrued distance/total moving time). "Ignoring zeros" would amount a different extraction of "moving time" as compared to another calculation, and though this is possible, one wonders why they would have two different methods for calculating moving time - which after all, has to be extracted from the same original data, whether they plot it or not.
Clearly *something* is different and smoothing is a good suspect, but again it's odd that it would result in a systematic bias.