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You are looking for what is called the "strongly connected components" in graph theory jargon. These network islands can be computed in QGIS with the grass plugin - See v.net.components.


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Finnish Airports Isochrones using the Interpolation plugin Site analyses can benefit greatly from using “drive-time” isochrones to define the study area. Drive time isochrones are often significantly different from simple buffer areas which disregard natural barriers such as rivers or slow roads. ...


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You should use osm2pgrouting to import the osm data into you DB, it's a command line tool that will automatically create the appropriate graph for pgrouting. http://www.pgrouting.org/docs/tools/osm2pgrouting.html


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The first argument of a pgRouting shortest path query is an SQL statement. You can provide any query there, which returns: id source::integer target::integer cost::double precision What does the query SELECT gid AS id, source::integer, target::integer, length::double precision AS cost FROM roads WHERE traffic != false; return? If ...


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When you use OSM data for pgRouting, then you need to use special import tools. This will automatically solve your problem. To get started I highly recommend you the pgRouting workshop, because it will exactly guide you to get pgRouting work with OSM data: http://workshop.pgrouting.org/


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The file osm2po.config, which can be obtained from the downloads tab on the osm2po page, contains a table with four column, defined as: 1) concurrent order 2) class (1-127) 3) default speed in kmh 4) allowed transportation type (optional) - since v4.5.30 And here are some sample rows, which I think explain where the 12, 51, etc, you are ...


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If you are into Java and want Flexibility, Graphhopper is an excellent alternative. Peter, the project lead, actively encourages extensions and changes and the community is very responsive. Graphhopper works differently to Pgrouting (I use both) and it is extremely fast. Instead of using a PostGis database, Graphhopper builds its graphs direct form the .pbf ...


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There should be no problem using PgRouting for this purpos, and it should be pretty straight forward to prepare your data as routable network. I build a network similar to yours based on transtools data for Europe, and it was working within an hour. Load the data into the database in whatever way you have them, and they can be prepared with SQL - use this ...


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Try running the query in a terminal window or pgAdmin3 to see if it works there. If you want to visualize the routing query in QGIS look at the workshop: Create a database connection and add the “ways” table as a background layer. Add another layer of the “ways” table but select Build query before adding it. Then type the following into the SQL where ...


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It's the ordering of arguments. In your initial query, pgr_analyzeGraph('Highway','the_geom',0.0001), you should swap the 2nd and the 3rd argument. Since 'id' is the default value of if field, there is no need to explicitly define the id field. You may try SELECT pgr_analyzeGraph('Highway_empty', 0.00001, 'the_geom') and it should also work.



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