[OSM-talk] Fixing broken multipolygons

[Florian Lohoff]

On Wed, Feb 15, 2017 at 04:20:53PM +0100, Jochen Topf wrote:
> Yesterday I launched several Maproulette challenges that allow you to
> easily help with the "cleaning up" effort. Read
> http://area.jochentopf.com/fixing.html for more details on those
> Maproulette challenges. This is a huge effort that will take a long time
> and we really need any help we get. The challenges posted today are only
> the beginning. They only show the about 6,500 ways worldwide tagged as
> buildings (with less than 100 nodes) where the way intersects itself.

After Europe was fixed in <24h it seems i started to wade through Africa
and i am seeing some error class which makes me wonder is somebody did
some large scale autonomous Aerial scan for buildings.

There are literally hundrets of building which have 4 edges as nodes
but them beeing connected over cross so that a construct like a
butterfly resembles.

I have never seen a human produce something like this.

One can easily spot human errors like using "extrude" and Josm leaving
the old edges in place, "duplicate" edges which make the polygon
self-intersect within 10cm etc ..

Flo
-- 
Florian Lohoff                                                 f at zz.de
             UTF-8 Test: The 🐈 ran after a 🐁, but the 🐁 ran away
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