[OSM-dev] Simplifying data for routing

[Nolan Darilek]

On Jul 28, 2007, at 10:29 AM, Frederik Ramm wrote:

> Oh yes, we expect people to place nodes at intersections. If two  
> roads intersect without a node being put there, that's either  
> lazyness or a forgotten "bridge" tag or so. I'd suggest to use  
> those nodes that are intersections and drop the rest.
>
OK. So in the case of more than 4-way intersections, or intersections  
added later, are mapping programs/map editors smart enough to use pre- 
existing nodes? So I wouldn't have, say, three separate nodes in an  
intersection?

How might I go about determining whether a node is an intersection?  
The only solution I can think of is to track whether a given node is  
referenced from two different ways. Is that reliable?
>
> I believe there are some routing functions available for PostGIS  
> (google for "pgRouting"); if you put your data in the format they  
> expect, you might get away without any coding at all.
>
Cool, thanks, I'll check that out.