R: [postgis-users] routing and network analysis
Paolo PP. Pulli
Ppulli at edinform.it
Wed Jan 19 06:01:19 PST 2005
> Hi Robin,
> I have built a network building/walking framework that is precisley
> solving problems like the one you describe. It is part of the geotools
> project, in a module called "graph". See http://www.geotools.org/
> The way it works is you pull all of the relevant geometries (in your
> case road linestrings) out of the database and build a graph. Then
> the graph to answer questions like give me the shortest path from node
> to node 2.
> The main drawback is that the entire graph has to be stored in main
> memory. So if you are working with mass amounts of data then you might
> need something a bit more elegant.
> Let me know if you are interested and I can send you some sample code.
I'm very interesting about routing and network analysis.
Could you send me your sample code (with data!?), please.
> > a) I have access to road network data. I've heard the new GRASS can
> > be used to do network analysis. anyone heard if it would be
> > in combination with postGIS, or could suggest another package?
Yes, Grass is powerful to do network analysis but, for my knowledge and
my needed, is not thread safe therefore it's not suitable for example in
webGis and it is to prefer(?) PostGIS sql-procedure (any idea on it?)
> > b) as an alternative, can anyone suggest or point to an efficient
> > approach for computing the shortest path between two points which
> > not go through, say, water polygons?
Justin, your solution solve this question?
I'm just download GeoTools and I'm going to study it!
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