Changes in version 2.2 (2026-04-29)                   

  - Added topo.dist parameter to movecost(): when set to TRUE, the
    function calculates accumulated cost using topographic (surface)
    distance rather than planar (horizontal) distance. This accounts for
    the additional distance incurred when traversing sloped terrain,
    providing more realistic walking-time estimates in mountainous
    areas. The correction is calculated as surface distance = planar
    distance times the square root of (1 + slope squared). For example,
    on a 30% slope, surface distance is approximately 4.4% greater than
    planar distance; on a 50% slope, approximately 11.8% greater.

  - The topo.dist parameter works with all available cost functions,
    though it is particularly recommended for time-based hiking
    functions. Users should exercise caution when applying it to
    metabolic energy expenditure functions, as these were typically
    derived empirically using planar distance measurements.

  - Added detailed documentation section explaining the topographic
    distance methodology, its mathematical basis, and guidance on
    appropriateness for different cost function types.

  - Propagated the new topo.dist parameter to all wrapper functions that
    rely on movecost() as internal workhorse: movealloc(), movebound(),
    movecomp(), movecorr(), movenetw(), and moverank(). Users can now
    control whether topographic (surface) or planar distance is used
    directly from each wrapper. The default value (topo.dist = FALSE)
    preserves backward compatibility, so existing code continues to
    behave exactly as in version 2.1.