[OSM-talk] The Venice Lagoon dried...

[Jon Burgess]

On Fri, 2008-02-29 at 14:33 +0000, Andy Allan wrote:
> It's fairly straightforward:
> 
> There are three sources of coastlines in the mapnik layer:
> 
> http://trac.openstreetmap.org/browser/applications/rendering/mapnik/osm.xml#L31
> 
>  * World-1 : zoom 0 to 6, very low detail
>  * world : zoom 7 to 9
>  * coast-poly : zoom 10+
> 
> The final one is derived from the coastlines in the database, but
> isn't automatically updated - it'll happen when Jon feels that it's
> worth doing by checking the state of play at
> http://tile.openstreetmap.nl/coastlines.html . You can tell the first
> two apart by checking Stockholm - the inland sea to the north-west is
> on world-1 (and coast-poly), but not world. On the cycle map I ditched
> the world layer and only render world-1 and coast-poly, but there's a
> performance impact on rendering the very-high-quality coast-poly at
> low zooms, never mind the problems with Greenland being missing etc.
> 
> In this case, it looks to me like the coast-poly didn't have the
> lagoon in it when Jon last synced, whereas it does now. Syncing isn't
> always a good idea, since there will be days when the whole world goes
> blue on the coastline checker, but I'm sure it'll be updated at some
> point.
> 

It look like a temporary glitch. I'm currently using the shapefiles
which were generated on Wednesday morning. The coastline checker shows
the lagoon to be filled correctly now. This should appear on the main
map next Thursday (or maybe earlier if the new tile machine gets fully
on-line before then).

	Jon