[OSM-talk] When will the next mapnik coastline update be?

Peter Körner osm-lists at mazdermind.de
Thu Dec 10 16:11:45 GMT 2009


Steve Bennett schrieb:
> So, my hard work tagging beaches and moving the coastline looks like crap:
> http://osm.org/go/uG4E@BCC
> 
> Anyone know how long it's likely to be until the next coastline update
> is taken into account by Mapnik?
> 
> (For bonus marks, can anyone explain what's special about coastlines,
> and why this happens?)
The almighty wiki can:

http://wiki.openstreetmap.org/wiki/Coastline

The main problem of showing coastlines from OSM data is that Mapnik 
really needs closed polygons. The polygon can (and normally should) be 
made of several ways, but the ways should join end-to-end and eventually 
loop back round without interruption, to close the polygon. An imperfect 
coastline with many small gaps, reversed ways and other defects will 
cause the polygon to break, and the coastline to be rendered incorrectly 
. One of the features of the Coastline error checker is to try and join 
coastlines in such a way as to make high-quality coastlines even with 
these imperfections. As the coastlines are uploaded and completed the 
quality can be checked.

Peter




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