[pgrouting-users] select multiple shortest paths from one to several points

[Daniel Kastl]

On Fri, Jul 19, 2013 at 2:45 AM, Nate Wessel <bike756 at gmail.com> wrote:

> I'm looking to select a number of shortest paths from one point to each of
> a set of points. For example, I would like to generate paths from my house
> to every coffee shop in the metro area.
>
> Conceptually, it seems like this should be a simple problem, but I'm
> running into issues when I try to construct a query to actually do it. I
> managed to get as far as getting a nearest-network-node ID for each of my
> coffee shops into a table by themselves.
>
> From that point, I get a little lost. As far as I can tell, I have three
> tables to join together somehow: The network edges table, the table with
> the destination node IDs, and the table that results from a shortest path
> query. It's simple enough to join the network edge table geometry to the
> result of a single path query. But how do I pass a variable from my node
> IDs table to the end-point parameter of a shortest-path function?
>
> When I tried something like:
>
> SELECT
> ....
> FROM destination_nodes, shortest_path(..., network_nodes.id ,...)
>
> JOIN network_edges ON ....
>
> I get an error saying I can't pass a variable from the same query level to
> the function.
>
> Can someone please help me understand how I need to structure this query
> to get the geometry of the paths associated with information from my
> destination_nodes table?
>
>
>
Hi Nate,

You could try the new pgRouting 2.0 (will be a stable release soon, I hope).
There is a new algorithm that can do 1 to many shortest path requests:
http://docs.pgrouting.org/v2.0.0-rc1/src/kdijkstra/doc/index.html

Daniel





-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
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