[R-sig-Geo] Distances in shortestPath function (package spatgraphs)

[Julian Burgos]

Great, thanks for the answer!

On mán 18.jún 2012 11:20, Julian Burgos wrote:
> Dear list,
>
> I have a question about the shortestPath function (in the package 
> spatgraphs... a very useful package but with very sparse 
> documentation).  The function finds the shortest connection between 
> two nodes in a graph.  According to the documentation, the usage of 
> the function is
>
> shortestPath(i, j, g, pp=NULL, dbg=FALSE)
>
> where i and j are the starting and ending nodes, g is the graph that 
> defines de edges, and pp is a point pattern.  If pp is given, "the 
> edges are of Euclidian length, otherwise each edge is of length 1.".
>
> So this is my question:  if I give a point pattern, does the 
> shortesPath function finds the shortest path in terms of distances 
> between nodes or in terms of number of nodes?  In other words, will 
> the algorithm select a shorter path in terms of distance even if it 
> goes through a larger number of nodes?  I am asking because my graph  
> is very dense (has lots of points) in some areas, and it is very 
> sparse in others.  I want to make sure that the algorithm actually 
> picks the track with the shortest distance and not the track with the 
> lowest number of nodes.
> Thanks!
>
> Julian
>


-- 
Julian Mariano Burgos, PhD
Hafrannsóknastofnunin/Marine Research Institute
Skúlagata 4, 121 Reykjavík, Iceland
Sími/Telephone : +354-5752037
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Netfang/Email: julian at hafro.is