The velocity data is only useful in its raw form like in real time.

OP: The greatly fluctuating speed output of my GPS Garmin 800 is annoying to me. Likely better with a cadence sensor

My favorite feature on the maiden voyage last night was being told I was off route when in fact I was right on the right road that I cycle every day, then it routed me in the wrong direction/wrong road. Who knows why.