[R-sig-Geo] shortest path

[Mathieu Rajerison]

Hi,


I've got a question which is graph-related.

Let's suppose I have a linear network.

I cut the lines at the intersections and get some vertexes and edges
connecting them

How can I turn this into a graph that I could treat in igraph?

I've put a line sample as attached file if any geohacker is interested in
facing the challenge ;)


Mat

2012/8/25 Karl Ove Hufthammer <karl at huftis.org>

> Barry Rowlingson skreiv:
>
> > [1] I think the zero indexing might be changing soon, or has
> > changed... Recent igraphs might be different,
>
> Indeed. From the release notes of igraph 0.6:
>
> ,----[ http://igraph.sourceforge.net/relnotes-0.6.html ]
> | The biggest change in the R interface is that starting from this version
> | vertices and edges are numbered from one. This change might be painful
> | for many people, because it makes already existing code incompatible with
> | igraph 0.6. To make the switch easier, there is now an igraph0 package
> | on CRAN; igraph0 uses 0-based vertex and edge ids, and it can be used
> | to run old code. Note, however, that igraph0 will not be developed in
> | the future. Please use the igraph package for current and future work.
> |
> | (Also note that in Python and C vertices and edges are still numbered
> | from zero, as these languages traditionally use zero-based indexing.)
> `----
>
> --
> Karl Ove Hufthammer
> E-mail: karl at huftis.org
> Jabber: huftis at jabber.no
>
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