[pgrouting-users] Dangling sub-networks

Sun Jun 27 14:16:26 PDT 2021

Hi Imre

It seems like something I can make work to identify small subnets/components. Thanks.

Would you happen to have a hint to how to delete such components from a network/topology?

Cheers
Hans

From: Pgrouting-users <pgrouting-users-bounces at lists.osgeo.org> On Behalf Of Imre Samu
Sent: 27. juni 2021 22:59
To: pgRouting users mailing list <pgrouting-users at lists.osgeo.org>
Cc: pgRouting developers mailing list <pgrouting-dev at lists.osgeo.org>
Subject: Re: [pgrouting-users] Dangling sub-networks

> Is there a way to identify (and potentially delete) such minor sub-nets?

IMHO:  this is similar for detecting "Component" ( https://en.wikipedia.org/wiki/Component_(graph_theory)<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FComponent_(graph_theory)&data=04%7C01%7Chsp%40ign.ku.dk%7C0080224f167f4bfad97d08d939ae6292%7Ca3927f91cda14696af898c9f1ceffa91%7C0%7C0%7C637604243862347472%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=gJ98Sl5TkTmIEfcuR137NEFMXHzJ6UzgTF8yc4vZXJI%3D&reserved=0> )
Have you checked the  https://docs.pgrouting.org/3.1/en/components-family.html<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.pgrouting.org%2F3.1%2Fen%2Fcomponents-family.html&data=04%7C01%7Chsp%40ign.ku.dk%7C0080224f167f4bfad97d08d939ae6292%7Ca3927f91cda14696af898c9f1ceffa91%7C0%7C0%7C637604243862352447%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=18ks3lmIRl1BLgtS%2FmPSjZ%2B7S3Q8r0IdufOdD871rA4%3D&reserved=0>  functions?

If you know the components - you can calculate the aggregated length of edges for each component.

Regards,
 Imre

Hans Skov-Petersen <hsp at ign.ku.dk<mailto:hsp at ign.ku.dk>> ezt írta (időpont: 2021. jún. 27., V, 21:42):
Hi list

I realize that the network (OSM) I am working on is not always connected as it should (big surprise ☺)…. Some parts are disjoint from the rest – even when not being situated on islands, or other places where a disjoint is expected. Accordingly, routes from nodes on such sub-nets cannot be generated.

Is there a way to identify (and potentially delete) such minor sub-nets? For instance by asking for the aggregated length of edges of a sub-net.

[cid:image001.jpg at 01D76BAA.65BBFC70]

Hans Skov-Petersen
Professor of Geoinformatics

University of Copenhagen
Department of Geosciences and Natural Resource Management
Section of Landscape Architecture and Planning
Rolighedsvej 23
DK-1958 Frederiksberg

DIR +45 35 33 18 16
MOB +45 23 82 80 45
hsp at ign.ku.dk<mailto:hsp at ign.ku.dk>

[Title: SD_Logo]

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