[OSM-dev] osm2pgsql patch for nested relations

[Frederik Ramm]

Hi,

On 02/19/12 13:46, michael63 at digital-filestore.de wrote:
> I dug into the sources and found a solution which is attached as a
> patch.

I know that there are precedents, but I am highly averse to coding 
specific relation types into osm2pgsql.

I would favour a generic solution of one could be found.

The problem that I see is there are two different logical things that 
you would like to do with nested relations - one is pushing the geometry 
up, the other is pushing the tags down.

For example, if you have three hiking relations (e.g. "cross country 
footpath noth", "cross country footpath central", "cross country 
footpath south") then they will sometimes be combined into a master 
relation "cross country footpath". In this case, you'd ideally create 
*one* line geometry for "cross country footpath" by pushing up the 
geometries into the parent relation.

OTOH, if I understand you correctly, you would not like to have *one* 
geometry for everything contained in the route_master, but just push 
down some of route_master's attributes.

This is much more than just an osm2pgsql problem; everyone who wants to 
do something meaningful with OSM data must know how to interpret it. If 
we start coding special cases into osm2pgsql, we have to code the same 
special cases into lots of other applications too.

Bye
Frederik

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