Hi,
I think you can use SANET(http://sanet.csis.u-tokyo.ac.jp/) to create two
csv files: nodes and edgelist file which has three columns(fromid, toid,
edgelength), and it will be easy to create a graph matrix from these two
files.
Hope this helps.
Binbin

2010/12/4 Sadz A <sadz_a1000@yahoo.co.uk>

> I have some networks in GIS shape file (vector) format, the data I have are
> road
> maps that I digitised from satellite images in ArcGIS. (I can change them
> to
> raster or Ascii), is there a way to convert them into matrix that can be
> loaded
> and analysed with igraph in R?
> I would like nodes to be the points at which two lines/roads cross or a
> line/road turns at a right angle, and, I would like the edges to simply be
> how
> the various nodes/points are connected, they do not need to be directional
> or
> contain any information on flow etc.
> I would like to get a matrix out that shows how the network is built,
> for example point a and b are connected by edge 1, and point a and c are
> connected by edge 2.
> (Someone on the igraph mailing list suggested that I try this list).
>
> I'm very new to network and spatial analyses,
> Any and all help is really appreciated
> Thank you
>
>
>
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