[OSM-dev] Ways with 40k nodes, was: osmosis pgsql schema

Frederik Ramm frederik at remote.org
Fri Oct 31 14:45:43 GMT 2008


Dave Stubbs wrote:
> I'm all for an API hard limit of 1000 nodes in a way. That wouldn't
> impact any normal stuff, but would put a stop to megaways pretty
> quickly without the need for a re-education programme :-)

Fine with me.

I think this can (and should) be worked on at different levels.

1. Fix all ways with more than a few thousand nodes; repeat checks 
regularly. Timeframe: can be done tonight.

2. Start using an "area" relation (or allow multiple interconnected 
"outer" parts in the existing "multipolygon" relation) to be able to 
model large areas (where the circumference has more nodes than the node 
limit and thus must be split). Requires a (relatively minor, I guess) 
modification to osm2pgsql/osmarender, and to editors which are 
area-aware (if unmodified, editors will display these area outline 
segments as lines which doesn't hurt). Timeframe: a few days.

3. Build a node limit into the API. Timeframe: could do quickly if 
required but could also do it for 0.6.

4. Redesign the whole data model to allow "partial checkouts" of ways 
and generally switch over to Stefan de Konik's software which is better 
in any respect anyway (although I haven't yet understood the big 
difference between checking out part of a way and checking out a whole 
way that is part of a grouping relation). Timeframe: Maybe sometime.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

More information about the dev mailing list