[OSM-dev] get node data from flatfile

Paul Norman penorman at mac.com
Thu May 7 19:00:36 UTC 2015


On 5/7/2015 2:58 AM, Walter Nordmann wrote:
> Hi,
>
> at the moment i'm using osm2pgsql with slim-mode + flatfile for my imports
> and diff-updates and everything is running fine.
>
> But now i need to create pbf-exports of my database and i would like to
> access the node-data of the flatfile, because planet_osm_nodes is empty
> (whicht is ok).
If you're speaking of the OSM PBF format, the osm2pgsql schema is 
ill-suited for this, as it doesn't have all the metadata needed.
> Is there any way to access those nodes by osm_id? I tried to write a litte
> program starting with node-persistent-cache-reader.c but i did not manage
> it. Many nodes are missing.
As Frederik mentioned, there's a bug. Make sure you're using 0.87.3 or 
later, not 0.87.3-dev.

> At the end i would like to write my own pg/plsql-Function get_node(osm_id)
> which gives me the geometry of that node (reading the flatfile of course).
The right way to do this is probably to implement a foreign data wrapper 
(FDW) as a PostgreSQL extension reading the flat-nodes file. This would 
let it appear as a table and you could then JOIN to it and interact with 
it as you normally would.

http://pgxn.org/dist/oracle_fdw/ and 
http://www.postgresql.org/docs/9.4/static/postgres-fdw.html can give you 
an idea how you interact with a FDW.



More information about the dev mailing list