[postgis-users] OSM post import questions

[Imre Samu]

Hi Tom,

> osm_id field contains non-unique values as well as negative values

This is normal.   Osm2pgsql optimised for rendering.
- The osm2pgsql program now  spliting long ways after around 1 degree or
100km

https://github.com/openstreetmap/osm2pgsql/search?utf8=%E2%9C%93&q=Split+long+ways

- "--multi-geometry (-G) is necessary for most analysis as it prevents
MULTIPOLYGONs from being split into multiple POLYGONs ..."
https://github.com/openstreetmap/osm2pgsql/blob/master/docs/analysis.md

- negative values:   relations

https://help.openstreetmap.org/questions/2259/is-there-a-reason-why-osm2pgsql-produces-negative-osm_id-values

The easy solution for a primary key :    ALTER TABLE tablename ADD COLUMN
gid SERIAL UNIQUE;
(from https://github.com/openstreetmap/osm2pgsql/issues/446 )

Regards,
 Imre


2015-11-23 20:23 GMT+01:00 Thomas Endres <endres.thomas at gmail.com>:

> Hi,
> I have a couple post-import questions regarding North America osm data -
> hoping someone can help.
> Using the following with Postgres 9.4.5 and PostGIS 2.2 on an ubuntu
> instance.
>
> osm2pgsql --create --slim --cache 14000 --number-processes 4 --hstore -d
> osm --flat-nodes /usr/local/osm/flat_nodes.bin --style
> /usr/local/osm/default.style --multi-geometry
> /tmp/north-america-latest.osm.pbf
>
> 1- I'm trying to add a primary key on a few tables (on the osm_id field)
> for use in QGIS.  Problem is the planet_osm_line table for example errors
> as the osm_id field contains non-unique values as well as negative
> values.(?)
> Is the slim mode or flat-nodes causing me problems?
>
> 2- Should I have used the -l switch on import for epsg:4326 - I used
> nothing and assumed it would default to 900913?
>
> Thanks!
> -tom
>
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