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

Matt Amos zerebubuth at gmail.com
Fri Oct 31 15:00:39 GMT 2008

On Fri, Oct 31, 2008 at 2:53 PM, Stefan de Konink <stefan at konink.de> wrote:
> Matt Amos wrote:
>> quick question: if your schema used ordered relations instead of ways,
>> do you have an unordered relation type as well?
> That is a client rendering issue. The order is maintained as how it is
> inserted with an explicit idx. If mapnik/geoserver doesn't care about order
> and it is just a bunch of nodes all being campingplaces, it is just that.

would you represent a Y-shaped road as three relations, then? one for
the left fork, one for the right stem as a way-relation, then another
to group them together?

>>> The amount of tables is reduced, that means the amount of joins are
>>> reduced. And the indices required for database searches are now more
>>> efficient. Queries therefore get shorter, no need for a specific way
>>> renderer.
>> except when your relation doesn't relate linear features.
> What do you mean with linear features? The relation still has the ability to
> relate nodes or a relations. So I don't really see what you mean.

when you say "no need for a specific way renderer" - there is still a
need, as (in your example) you wouldn't want to render a bunch of
camping nodes as a linear feature. you'll also want to render
buildings filled. in other words: there isn't a single, specific way
renderer anyway because tag inspection is required.



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