[pgrouting-users] Fwd: Re[2]: How to populate already existing "road_noded_vertices_pgr" table?

Vladimir fl_v at inbox.ru
Thu Aug 28 23:36:41 PDT 2014

Thanks Daniel

Now I add new data in the network through QGIS (GRASS feature v.clean creates the segments from roads perfectly) and the DB trigger keeps  the "road_noded" and "road_noded_vertices_pgr" tables duly.


Mon, 25 Aug 2014 11:53:08 +0200 от Daniel Kastl <daniel at georepublic.de>:
>On Mon, Aug 25, 2014 at 11:00 AM, Vladimir  < fl_v at inbox.ru > wrote:
>>Hi All
>>I have a road network with appending a new segments sometimes.
>>Then I copy the new segments into my "road_noded" table and execute 
>>SELECT pgr_createTopology('roads_noded', 0.1, 'geom', 'id',rows_where:='id > a last id')
>>for affecting on the new segments only. But this action recreates my "road_noded_vertices_pgr" table completely for the new segments instead of appending the new vertices and referencing them to the new segments.
>>1) Is pgr_createTopology only for create not for update? Somebody knows other method or some trick?
>Yes, this function does not do updates.
>If you add or modify roads later, and if you don't want to keep old node ID's, then you can't use this function.
>>2) Could I use native Postgis functions (ST_StartPoint,ST_EndPoint etc) in the event if no possibility?
>I don't understand what you mean with "event", but yes, you can use any PostGIS function to handle the updates. You could for example a trigger function.
>Georepublic UG & Georepublic Japan
>eMail:  daniel.kastl at georepublic.de
>Web:  http://georepublic.info


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