topic Re: Energy based least cost path in Archaeology GIS Questions

Energy based least cost path

PanosTzovaras — Sat, 30 Dec 2017 14:55:44 GMT

Hi there,

I am trying to generate a least cost path taking into consideration the energy (calories) expended crossing a given distance. So I need to create a friction surface, based on a slope, representing the energy needed to cross a given distance.

I have made a similar surface by using the hikers equation. However, I don't know how can I do something similar but with energy.

Any suggestions/solutions?

Thanks

Re: Energy based least cost path

DanPatterson_Retired — Sat, 30 Dec 2017 19:20:26 GMT

Path Distance Analysis would be something to examine

Re: Energy based least cost path

JamesNewhard — Sat, 30 Dec 2017 19:32:05 GMT

I and my colleagues played around with this issue in developing some LCP modelng for the Argo-Saronic region: Newhard, J.M.L., Levine, N.S., and A.D. Phebus (2014). "The development of integrated terrestrial and marine pathways in the Argo-Saronic region, Greece." Cartography and Geographic Information Science 41.4: 379-390. https://doi.org/10.1080/15230406.2014.925786. We employed both several walking models (Tobler's and Naisthmith's) along with an effort algorithm that we pulled from a study conducted originally in Italy (citation escapes me).levinen

Re: Energy based least cost path

PanosTzovaras — Sat, 30 Dec 2017 19:59:36 GMT

That's really useful, and really thorough research, cheers. So, time-energy in one formula? Great. I used Tobler's equation too, and I was thinking to use Pandolf equation, but I am not so sure for the latter.

Re: Energy based least cost path

PanosTzovaras — Sat, 30 Dec 2017 20:00:22 GMT

Thank you

Re: Energy based least cost path

JamesNewhard — Sat, 30 Dec 2017 20:08:30 GMT

We're in the process of turning the model (originally worked out in ModelBuilder) into a more user-friendly process by streamlining out the processes in Python. Eventually, the game will be pushed onto our GitHub.

Re: Energy based least cost path

PanosTzovaras — Sat, 30 Dec 2017 20:19:17 GMT

Well, that's a game changer. I will be on the look out to see how your work will be developped.

Re: Energy based least cost path

PanosTzovaras — Sun, 31 Dec 2017 16:16:49 GMT

For anyone interested or with the same issue:

Appart from James' solution, which I highly recommend, there is another formula (pandolf's):

Generate a slope (percent_rise), use the raster calculator and divide your slope in percent map by 100, giving you a dh/dx. Then use a formula {e.g. Pandolf's formula: M=1.5*W+2.0*(W+L)*((L/W)*(L/W))+η*(W+L)*((1.5*V)*(1.5*V)+0.35*VG) }*

Then you just have to covert KM per W to W per KM (1.0/output) and afterwards, if you want you can also convert to W per M (output2/1000)

*W=weight, L=external load in kg, V=walking speed, G=slope, η= terrain coefficient