[OSM-dev] support for osm2pgsql with relation type=route

Martijn van Oosterhout kleptog at gmail.com
Sun Apr 13 16:00:06 BST 2008

On Sun, Apr 13, 2008 at 10:42 AM, ivom <ivo.vdmaagdenberg at pandora.be> wrote:
>  I was wondering when route relations are processed with osm2pgsql. In the
>  current svn tree I can see that there has been some effort in adding
>  polygons but the code has been functionally disabled. Does not work well?
>  Is there someone who can tell about near-future support for relations with
>  type=route? There seem to be at least 2 public sites that are able to
>  process relations successfully. Where is that code? :)

The problem is scaling: to process a route relation you need to have
the ways and you don't have the memory ot store all the ways. The ways
are processed before the relations. However, if you run in --slim mode
it will store all the ways in the database and then you can handle the
route relations.

Yesterday I committed some changes which make slim-mode almost as fast
as non-slim-mode (well, only 2x as slow in the simple case, I havn't
tested the whole world case). I have the code to handle route
relations and will be adding it shortly, however, it will only work in
slim-mode, because you don't have the memory to do it in

The downside is you need a lot more diskspace if you want to handle
the whole world. I'm estimating 40-60GB but I havn't been able to test
it yet. I may be able to get that down some, but it's a work in

So in short, there are two places that do it, but only for small parts
of the world where the problem is easily managable. There are other
approaches, like scanning the file twice, but I'm sort of aiming here
to be able to apply the daily diffs which limits certain trade-offs.

Hope this helps,
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/

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