[OSM-dev] osm2pgsql invalid polygons

[Sven Geggus]

Ramas <ieskok at ramuno.lt> wrote:

> how do you solve problem with skipped invalid polygons? 

Fix it in the osm database?

> with error:
> Self-intersection at or near point 2889220.2400000002 7470212.1299999999

This does not look as a valid polygon to me at leadt in OGC Simple
Features terms.  This could arguably get fixed in osm2pgsql code
because it is know how it is meant to be in this case, but it is not
a valid OGC Simple Features polygon.

Just add an additional way around 160596899 and 160596916 and declare
this one of type inner.

> I patched osm2pgsql and it allows to import such polygons. Mapnik renders
> it correctly. 

Not a good Idea IMO because there is more than Mapnik and quite a lot
of the spatial operations in postgis will not work with invalid
geometries.

>Does we need such validations?

I definitely think we do. If osm2pgsql does import and render invalid
polygons they will never get fixes in the database.

Sven

-- 
Trotz der zunehmenden Verbreitung von Linux erfreut sich der Bär,
und - dank Knut - insbesondere der Eisbär, deutlich größerer
Beliebtheit als der Pinguin. (Gefunden bei http://telepolis.de/)
/me is giggls at ircnet, http://sven.gegg.us/ on the Web