I'm using ESRI's Path Distance Analysis based on Toblers hiking function to estimate the walking time from an archaeological site to establish it's context. Each color represents an hour of walking time, the red line is river which I made 100 meters wide and re-classed to NoData. I think the first four hours of walking make a lot of sense.
But what is going on with when the model hits the coast line?
Especially with the middle blue value (the 7th hour of travel) - Tobler's estimates travel at roughly 5km per hour optimal speed but along the coast it is estimating travel at 16km an hour.
Is this edge distortion?