[pgrouting-users] Cleaning multilinestring vector network for routing via kDijkstra

[Daniel Kastl]

Hi Eyad,

As Steve already said, multilinestrings are not really something good for
pgRouting.
But often there are no real multilinestrings at all, and you can change the
geometry type.

How you can test, if your network has multilinestrings and how to get rid
of them (if they don't contain mutli-geometries), see this link:
http://gis.stackexchange.com/questions/116414/take-from-multilinestring-the-start-end-points/116444#116444

Also you mentioned that your network data is in unit "millimeters", and you
run the topology function like:

Select pgr_nodeNetwork ('schema.table', 0.0001, 'id', 'geom')

This means, that you have a snapping tolerance of 0.0001 mm if your network
is not properly digitized. I would assume that CAD data is correct, but
still a snapping tolerance of 0.0001mm is so small, that you could just
increase it to 1 for example, or even higher. Check, if in your network
edges are really connected.

Daniel




On Tue, Dec 16, 2014 at 4:35 AM, AUS - Eyad <b00038807 at aus.edu> wrote:
>
> Thanks Steve..
>
> I tried using st_geometryn as follows:
>
> pgr_kdijkstraCost(
>     'SELECT id, source, target, (st_length(ST_GeometryN(geom,1)) * 0.001)
> as
> cost FROM schema.table',
>     id, (SELECT array_agg(id) FROM schema.table), false, false
>   ) as cost
> from schema.table
>
> I got exactly same results as before.. Cost="-1" which means that there is
> no connection
>
> Looking forward for further assistance ASAP
>
> Regards,
>
> Eyad
>
>
> -----Original Message-----
> From: pgrouting-users-bounces at lists.osgeo.org
> [mailto:pgrouting-users-bounces at lists.osgeo.org] On Behalf Of Stephen
> Woodbridge
> Sent: Monday, December 15, 2014 10:45 PM
> To: pgrouting-users at lists.osgeo.org
> Subject: Re: [pgrouting-users] Cleaning multilinestring vector network for
> routing via kDijkstra
>
> Eyad,
>
> There has recently been a bug reported against pgr_nodeNetwork and it
> contains a patch to fix that problem. See:
> https://github.com/pgRouting/pgrouting/issues/280
>
> If you have multilinestrings then you might want to try something like:
>
> st_geometryn(multiline, 1)
>
> so you just select the first linestring in the multilinestring.
>
> -Steve
>
> On 12/15/2014 12:24 PM, AUS - Eyad wrote:
> > Hi All,
> >
> > As I'm still struggling to make my network routable, I tried using
> > pgr_nodeNetwork (instead of using v.clean), as follows:
> >
> > Select pgr_nodeNetwork ('schema.table', 0.0001, 'id', 'geom')
> >
> > But I got the following Error:
> >
> > line_locate_point: 1st arg isnt a line
> >
> > CONTEXT: SQL statement "create temp table inter_loc on commit drop as (
> > select * from (
> >
> > (select l1id, l2id, st_linelocatepoint(line,source) as locus from
> intergeom)
> >
> > union
> >
> > (select l1id, l2id, st_linelocatepoint(line,target) as locus from
> > intergeom)) as foo
> >
> > where locus<>0 and locus<>1)"
> >
> > PL/pgSQL function pgr_nodenetwork(text,double precision,text,text,text)
> > line 184 at EXECUTE statement
> >
> > I removed line 184 from my table but still getting same Error!
> >
> > Afterward, I tried calculating the costs using pgr_kdijkstraCost, but
> > unfortunately most of the results are "-1" which means that there is no
> > connection!
> >
> > Important note: my network is somehow accurate (done on CAD), but I
> > think this is a normal cleaning that every expert of you may take it for
> > granted
> >
> > Please assist in resolving this issue (even by suggesting new
> > tool/function) because my time is becoming tight and this is my first
> > real/full application using pgRouting
> >
> > Regards,
> >
> > Eyad
> >
> > *From:*AUS - Eyad [mailto:b00038807 at aus.edu]
> > *Sent:* Monday, December 15, 2014 12:44 AM
> > *To:* 'pgRouting users mailing list'
> > *Subject:* Cleaning multilinestring vector network for routing via
> kDijkstra
> >
> > Hi All,
> >
> > I'm facing a serious issue preparing my multilinestring vector network
> > for routing.
> >
> > I imported my vector network from CAD file. Obviously, there are some
> > areas where lines are intercrossing still not routable_through;
> > although, they are connected to each others!
> >
> > I used V.Clean (advance) to clean the network before importing to the
> > database. I tried (break, snap, bpol, etc) alternatively but still not
> > sure which one is the proper tool. Also I'm finding it hard to set the
> > parameters because my vector network is obviously imported in
> > millimeters while the network is spread on a length reaching 700m from
> > start to destination from some ends.
> >
> > I'm testing the results via shortest_path plugin before I import to
> > DataBase. In few successful cases using shortest_path, afterwards the
> > network gets to lose a lot of elements while importing to DB (i.e. 600
> > features only written from 700).
> >
> > If there are other ways to make the network clean and routable, please
> > suggest
> >
> > I'm using QGIS 2.4.0 and pgRouting pg93-binaries-2.4.0
> >
> > Regards..
> >
> > Eyad
> >
> >
> >
> > _______________________________________________
> > Pgrouting-users mailing list
> > Pgrouting-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/pgrouting-users
> >
>
> _______________________________________________
> Pgrouting-users mailing list
> Pgrouting-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2015.0.5577 / Virus Database: 4235/8736 - Release Date: 12/14/14
>
> _______________________________________________
> Pgrouting-users mailing list
> Pgrouting-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
>


-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.info
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/pgrouting-users/attachments/20141216/08b108f2/attachment.html>