[OSM-dev] multipolygon inherits from tags way that are neither inner nor outer

Frederik Ramm frederik at remote.org
Mon Jan 16 23:13:53 GMT 2012


On 01/17/2012 12:00 AM, Pieren wrote:
> For a relation of type "boundary", it make sense to link the
> administrative boundary with its administrative centre.

Yes, but the link should be indirect. The boundary should be linked from 
the country, and the administrative centre should be linked from the 
country too. Boundaries dont' have administrative centres. Neither do 
they have capitals.

> I also don't understand why the "roles" would be ignored in
> multipolygon relations. Then why JOSM is complaining when the role is
> undefined, although the wiki says the opposite.

It depends on what you want to do. If you want to draw the best possible 
map with the data you have, and have no option of asking the user what 
the hell he meant when he entered that, then you will ignore roles (and 
compute them yourself) because otherwise a significant percentage of 
multipolygons will appear broken.

It would be good if roles were always well defined, that's why JOSM 
reminds you of it, but it would not be good if a rendering engine would 
expect roles to always be well defined.


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

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