[GRASS-user] obtaining pairwise least-cost distances in meters

[Anders Gonçalves da Silva]

Hello all.

I have a set of samples in a landscape. I want to create different friction maps based on landscape features (i.e., presence/absence of roads, vegetation type, etc.) to understand animal movement between habitat patches. I have used v.distance to calculate the pairwise distance among the samples (which I assume is the Euclidean distance). But, I would like to incorporate other features. 

I have a dem, a vector map with points, and a vector map with vegetation types and other land use types all in one mapset.

I tried to use r.walk to calculate the distance among the sample points based solely on the topography by creating a friction map with all cells =1:

r.walk elevation=dem friction=area1 out=null.cost start_points=points stop_points=points #similarly to what v.distance does, ie, the start points are the same as the end points.

Computations proceed to the end, but when I try to visualise the results, nothing appears on the d.mon.

Ideally, I would end up with different matrices of pairwise distances for each different friction map, which represent different hypotheses about how the animals interact with the landscape.

I am not sure what I am doing wrong, or even if this is the most efficient way of approaching this problem. Any assistance would be appreciated. 

Thank you.

Anders.