Devices (Apple Watch, some GPS units) record 0.0 when they lose barometric/GPS
lock mid-activity. The old accumulation committed these as real sea-level points,
inflating both gain and loss by the current elevation (e.g. 792m dropout on the
Cosmo Walk added ~1584m of phantom gain+loss).
Fix: skip any elevation value < 1.0m when the current committed elevation is
significantly above zero (> threshold). Gradual legitimate descents to sea level
are unaffected because intermediate values are committed along the way.
Add --recompute-elevation flag to bincio render to backfill existing activities.
Davide Scaini
3b675a68b0