[Tilesathome] Frustrated about oceantiles

[Martijn van Oosterhout]

On Mon, Dec 15, 2008 at 9:32 PM, Andre Hinrichs <andre.hinrichs at gmx.de> wrote:
> I'm working on the oceantiles for three weeks now changing over 2200 tile
> definitions and am getting more and more frustrated. The decision about
> whether a tile is sea/land/mixed is sometimes very hard and often vague. I've
> seen cases where the coastline is about 0.5 meters away or within a tile. So
> the next time somebody is moving a single node there may harm the tile
> rendering.

It's a terrible solution, but we havn't got any better ones yet. FWIW
the oceantiles.dat should be directly generatable from the coastline
checker (http://tile.openstreetmap.nl/coastlines.html) but no-one has
taken the effort. Might be less work than changing them all by hand.

> I was thinking a lot about this and already dreamed of it... I cannot see the
> necessarity for a 'mixed' state. The oceantiles.dat should give the server
> the possibility to serve a colored image where no tile information is present
> and the renderer should only upload an empty tile if it really cannot decide
> whether there is land or sea. The renderer should only take the state of the
> tile as background color if there is no coastline or water or land in the
> rendered OSM data. Wherever the renderer is able to decide this on basis of
> the OSM data it should do so where the oceantiles.dat is not necessary for,
> is it?

You're right, it should be able to but it doesn't. It's a but which I
didn't know about when I made the first version of coastlines.dat.
close-areas is only able to determine if a continuous piece of
coastline *intersects* the edges. This is messy and unneccesary.
Definitly some I want to fix at some point (if someone doesn't beat me
to it).

Mvg,
-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/