Where "slow" starts, from the speeds of a run's moving seconds. On a
run/walk run they fall in two groups, walking and running, with few
seconds between; the cut-off goes in that gap, so a walk whose speed
wavers isn't cut into pieces. The split is the one that keeps each group's
speeds closest together (Otsu's method), and is used only when the slower
group is big enough, clearly slower, and the gap holds fewer seconds than
the walking speeds do (and the slower group is under half the seconds and
at walking speed). Otherwise slow is under three quarters of the usual
speed. usual is the running group's middle speed when there are two
groups, else the middle speed of all moving seconds. Both are 0 for no
speeds.
Where "slow" starts, from the speeds of a run's moving seconds. On a run/walk run they fall in two groups, walking and running, with few seconds between; the cut-off goes in that gap, so a walk whose speed wavers isn't cut into pieces. The split is the one that keeps each group's speeds closest together (Otsu's method), and is used only when the slower group is big enough, clearly slower, and the gap holds fewer seconds than the walking speeds do (and the slower group is under half the seconds and at walking speed). Otherwise slow is under three quarters of the usual speed.
usualis the running group's middle speed when there are two groups, else the middle speed of all moving seconds. Both are 0 for no speeds.