[OSM-talk] Fixing broken multipolygons

Christoph Hormann chris_hormann at gmx.de
Thu Feb 16 09:53:42 UTC 2017


On Wednesday 15 February 2017, Sarah Hoffmann wrote:
>
> There are some notable holes, for example in the woods of
> Scandinavia. It would be great if they are gone by the time we
> switch the software.

A general recommendation here to the Scandinavian communities - you 
might seriously want to consider removing the forest/wood polygons from 
the old Corine landcover imports.  These are:

* factually very inaccurate, usually indicating this area is mostly tree 
covered rather than this area is actually forested.
* not aligned to other geometries, in particular water bodies.
* non-maintainable due to the polygons size leading to mappers widely 
drawing other stuff over it.

Examples:

http://mc.bbbike.org/mc/?lon=8.836311&lat=58.848538&zoom=14&num=3&mt0=google-satellite&mt1=mapnik&mt2=mapbox-satellite
http://mc.bbbike.org/mc/?lon=27.615479&lat=60.772083&zoom=13&num=3&mt0=google-satellite&mt1=mapnik&mt2=mapbox-satellite
http://mc.bbbike.org/mc/?lon=26.339005&lat=61.247215&zoom=13&num=3&mt0=google-satellite&mt1=mapnik&mt2=mapbox-satellite

Newly mapping wood areas from scratch here would likely lead to better 
and better maintainable data in the long terms.  You could even 
consider importing newer high quality data with a more sensible polygon 
size.

-- 
Christoph Hormann
http://www.imagico.de/



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