I was reading some literature dealing with least-cost path calculation and accumulate cost-surface generation using the Tobler's hiking function. I was reading this literature since I am trying to implement in R the generation of isochrones around a starting location (Integrating use of surface distance when calculating cumulative cost-surface based on walking pace?).
I can't understand what seems to me quite odd: some sources (e.g., Wikipedia) indicate that the speed predicted by the function is in KmH, while the author of the
gdistance R package (see this PDF at page 14) indicates that the off-path speed would be in meter-per-second (he actually indicates m/s).
I am having hard time in understanding which is correct. This is not a trivial issue since different results are bound to crop out using Kmh vs. m/s.