On 28-1-2011 23:07, Jon Burgess wrote:
The rendering of the OSM data in Japan was significantly slowed down by
the recent addition of a relation (id=1337942) describing a very large
natural=wood polygon. This has about 100,000 nodes in the outer ways and
another 100,000 nodes for the inner ways. This covers a large area and
Mapnik needs to process this relation for every tile inside this area.
To give you an idea of the sheer size of this relation: it (just the one
relation) is an 85MB .osm file. Encompassing an area roughly bounded by
Hachinohe in the north, to Ichinoseki in the south and Katagami in the
west to Miyako and the coastline in the east.
1 relation, 10865 ways, 414910 nodes
While this relation is huge, there are many other relations in that
imported dataset that are very large as well. I've seen a few in the
order of 2500 member ways.
It would be best if you could contact the person or persons importing
that dataset in Japan, and relay the gentle reminder that they may cut
that up into more manageable chunks, if possible.
While osm2pgsql already cuts up very long ways into more manageable
chunks, it doesn't do so for areas. Even if it did, that could bode
non-aesthetically pleasing trouble for renderings that use outlines or
patterns for those objects.
--
Lennard
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