mapper.hdist function computes the total distance traveled while going through the points in the sliding window in chronological order. This distance is in meters.
The distance used is the loxodromic distance aka rhumb line. As a consequence, elevation is not taken into account in the distance.
If a point has no position in the sliding window, it is ignored.
The associated location and elevation are those at the tick being computed if it is part of the sliding window.
mapper.hdist function can be applied to data of any type since it only considers locations.