[pgrouting-users] pass query results to routing function

[Hugh Kelley]

To follow up, the structure below seems to work fairly well for this. would
still be curious to see better options if anyone knows of any.

This is a little awkward since it ends up returning a results table that's
a single column that's a pseudo type record.

drop table if exists scratch.routing_pairs;

create table scratch.routing_pairs as (
    select
        dp1.tdg_id as origin_id,
        dp1.nearest_net_node as origin_node,
        dp2.tdg_id as dest_id,
        dp2.nearest_net_node as dest_node
    from
        automated.doors_and_parking dp1
        left join automated.doors_and_parking dp2 on st_dwithin(dp1.geom,
dp2.geom, 250)
    limit
        100
);

select
    pgr_dijkstra(
        'SELECT tdg_id as id, source, target, length_cost as cost FROM
automated.ped_network as edge_table where source is not null and target is
not null',
        origin_node,
        dest_node,
        false
    )
from
    scratch.routing_pairs
    ;

On Mon, May 9, 2022 at 3:22 PM Hugh Kelley <hghklly at gmail.com> wrote:

> Hi,
>
>
> I'm wondering if anyone has an example of a query that calculates routes
> between pairs of nodes  that is a subset of all the possible pairs in the
> network.
>
> I have a network with ~5297 nodes, for ~28 million possible pairs. I could
> calculate routes for all of these pairs and then use the subset of routes
> that i need, but it seems that there could be a way to calculate only
> routes for the ~17 thousand pairs I actually care about.  If possible I
> would filter to only calculate pairs where the origin node is
> ST_DWITHIN(a.geom, b.geom, 250), for example.
>
> is there a way to pass the results of a query to the pgr_dijkstra()
> function? I haven't seen an example of that as I've read through the docs.
> is there a way to apply a condition like st_diwthin() to the arrays passed
> to the function?
>
> thanks for any advice or suggestions, hope everyone's week is off to a
> good start.
>
> Hugh
>


-- 
Hugh Kelley
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