[Tile-serving] [openstreetmap/osm2pgsql] Use libosmium for geometry building (#684)

[Sarah Hoffmann]

> Additional note: If you assemble polygons in geographic coordinates and reproject them into other coordinate systems you can get invalid geometries. This is rare practically with mercator but if you want to make sure you only have valid geometries you need a validity check afterwards.

Reintroducing the validity check is something I'd like to avoid. It's expensive and we'd essentially have to reimplement whatever libgeos is doing. So the question is, does this have any practical implications for normal osm2pgsql use cases? If it only happens when using some obscure projections, then post-filtering is probably the better option. If there are practical cases for mercator projection we should check if we can catch these particular ones without going through the full-blown validation process.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/pull/684#issuecomment-277785264
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tile-serving/attachments/20170206/5f0bddb0/attachment.html>