[OSM-talk] Coastline?

Martijn van Oosterhout kleptog at gmail.com
Fri Sep 5 11:55:39 BST 2008


The coastline checker as a side effect produces the shapefiles for mapnik.

The reason is that the coastline in the database isn't a geometry, but
a collection of ways. The checker joins all the segments into several
million node linestrings and then chops it into peices again and makes
shapes mapnik can render.

It's possible the main site hasn't updated the shape in a while, so if
you've added stuff recently and it isn't appearing you might need to
prod someone.

Have a nice day,

On Fri, Sep 5, 2008 at 3:12 AM, Michal Migurski <mike at stamen.com> wrote:
> Hi,
>
> I'm trying to understand how OSM generates coastlines in Mapnik, to
> render my own tiles.
>
> I'm reading this:
>        http://wiki.openstreetmap.org/index.php/Coastline#Main_Mapnik_Layer
>
> It sounds as though there should be some presence of natural=coastline
> in the osm.xml stylesheet:
>        http://trac.openstreetmap.org/browser/applications/rendering/mapnik/osm.xml
>
> Instead, I see shapefiles. Are those derived from data in pgsql, or
> are they obtained from elsewhere? Why are they shapefiles instead of
> geometries from the database?
>
> -mike.
>
> ----------------------------------------------------------------
> michal migurski- mike at stamen.com
>                  415.558.1610
>
>
>
>
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-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/




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