Thanks Jeremy! I will take a good look on this.

On Thu, Aug 4, 2011 at 11:36 AM, <jeremy.raw@dot.gov> wrote:

> There is certainly no need to go anywhere near ArcGIS for this type of
> operation.
>
> The simplest approach would be to look at one of the packages that does
> shortest path evaluations on a network.  On CRAN, the igraph package
> lets you can do this pretty straightforwardly.  Alternatively, the
> travelr package on R-Forge (not actively maintained, but functional for
> this purpose) is also available.  Igraph is easier if you are
> comfortable with basic graph theory (and translating to and from the
> 0-based indexing that the current version of igraph uses for node/vertex
> numbering), whereas travelr may be easier if you are already comfortable
> with transport modeling.
>
> The basic steps are to convert your base map into a suitable
> graph/network format (e.g. via what igraph calls an edgelist) and then
> to use shortest.paths in igraph, or build.paths and skim.paths in
> travelr, to compute the matrix of distances.
>
> Igraph also has a help list where some of the set-up questions for this
> type of problem have already been addressed:
> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
> I hope that helps!
>
> Jeremy Raw, P.E.
> FHWA Office of Planning
> jeremy.raw@dot.gov
> (202) 366-0986
>
>
> -----Original Message-----
> From: r-sig-geo-bounces@r-project.org
> [mailto:r-sig-geo-bounces@r-project.org] On Behalf Of Raphael Saldanha
> Sent: Thursday, August 04, 2011 7:32 AM
> To: r-sig-geo
> Subject: [R-sig-Geo] Highway Distance matrix
>
> Hi,
>
> How can I compute a distance matrix of points (citys) based on a highway
> base map?
>
>
> Regards in advance,
>
> Raphael Saldanha
> saldanha.plangeo@gmail.com
>
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>
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>



-- 
Atenciosamente,

Raphael Saldanha
saldanha.plangeo@gmail.com

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