[R-sig-Geo] path distance maps with R?

[Roger Bivand]

On Tue, 26 Jun 2007, David March Morlà wrote:

> Dear all,
>
> I want to create port-based distance maps to analyse spatial
> distribution of fishing effort. I have tried to use ?distmap.ppp?
> function from spatstat, but this computes Euclidean distances and I want
> to take into account obstacles (i.e. islands) in the same way as Caddy
> and Carocci (http://www.faocopemed.org/vldocs/0000028/publi04.pdf). Have
> you got any suggestion to perform these path distance maps with R?

If you have access to a GIS, you might find it more appropriate. The 
r.cost module in GRASS can do this very effectively, having first 
converted the vector land mask to raster, spreading from vector points 
over a raster sea within the sea mask. Naturally, this is best for 
projected cordinates.

Roger

>
> Thanks,
>
>

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no