[OSM-dev] osmarender: need help on fixing problems with rendering big lakes
Frederik Ramm
frederik at remote.org
Tue May 8 10:13:07 BST 2007
Hi,
> On the main map at informationfreeway.org the lake is rendered a
> little bit strange. The same problem occures at the Lake of Geneva
> [2].
Provided that you're talking tiles at home*:
Some of the broken lakes - those where the coastline is one single
way - will probably be fixed magically once the tiles are re-rendered
with API 0.4 (which will deliver the whole way to the renderer,
unlike API 0.3 which delivered only a section of the way).
But in general, this is the "big area problem" that we've talked
about in the past, and it will be solved as follows:
* expand close-areas.pl, which currently in its first version only
supports coaslines, to support other types of areas like
natural=wood, natural=water, landuse=...;
* if areas become so big that they completely encompass a level-12
tile are (approx. 10km squared) and there is a danger of the renderer
downloading a bounding box inside the area without catching any of
its border segments, use "control nodes" distributed inside the large
areas to tell close-areas.pl whether the tile is "inside" or "outside".
Since the close-areas.pl mechanism is quite new, we thought we'd
first use it with coastlines for a while and start using it for other
areas when it is stable. But if you're desperate to get the lakes
right and speak Perl, feel free to have a go; close-areas.pl is in
SVN (applications/rendering/tiles at home). You can read more about
close-areas.pl here:
http://wiki.openstreetmap.org/index.php/Tiles%40home/Dev/
Interim_Coastline_Support
Bye
Frederik
*) t at h mailing list is in the queue.
--
Frederik Ramm ## eMail frederik at remote.org ## N49°00.09' E008°23.33'
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