Including rivers into Least Cost Path

RobertoFilloramo

Hi,

I want to include a river as possible path in the least cost analysis, hence not as barrier yet as a possible alternative route. I read about it in Wheatley-Gillings 2002 in which the authors say that it makes by creating a central corridor with a central low value and the surroundings with an high values in order to force the estimation to choose the river as path.

I looked for it in letterature, yet I didn't find anything that could give me a detailed answer.

Does someone know how to do that and how, afterwords, to include this friction surface into a more general one so as to estimate the paths?

Thanx

P.s. I use ArcGIS 10.1

DanPatterson_Retired

assign the river a raster value of 1.

perform a Euclidean distance from the river. 

take the inverse (1/above) of the above and multiply by some factor (ie 10, 20 whatever) and take the integer of that.

Effectively, the values beside the river will be high, decaying as you go away from the river.  but the river itself is low, so it will b e the preferred route... if not the only route.

There is no 'science' to this... it is an 'art' to create such a cost surface... experiment