On Tue, Aug 29, 2017 at 12:10:47PM +0200, Christoph Hormann wrote: > Date: Tue, 29 Aug 2017 12:10:47 +0200 > From: Christoph Hormann <o...@imagico.de> > To: talk@openstreetmap.org > Subject: Re: [OSM-talk] Multipolygon fixing effort done > > On Tuesday 29 August 2017, Jochen Topf wrote: > > We have completed the 7-months effort to switch away from old-style > > multipolygons and fix a lot of broken (multi)polygons. More about > > this on my blog: > > > > https://blog.jochentopf.com/2017-08-28-polygon-fixing-effort-conclude > >d.html > > First of all congratulations to what was achieved, i.e. a fairly massive > reduction in the number of errors. > > The sad news however seems to be that given the current circumstances > the number of errors will likely be back to near the pre-cleanup levels > in 2-3 years for many types of errors. > > From my point of view this is because in contrast to the old style > multipolygons where > > * the problem was fully eliminated in the data > * the most important data user (the standard map) was changed to not > interpret old style MPs any more after that > * the major editors had already ceased to generate old style MPs long > ago > > the circumstances that lead to the large number of broken multipolygons > are essentially unchanged. We certainly got rid of a number of errors > from bad imports and can hope that future imports will be better in > that regard but the problem that mappers introduce this kind of error > in manual mapping and don't realize they are making an error is > unchanged.
What has changed is that now without the complication of the old-style MPs it is easier to check for correctness of the data in editors and other tools. I hope that especially editor developers are looking at this problem more closely to identify common problems that can be fixed by better UI or better checking on their code. > Of the points above both completely eliminating MP geometry errors and > changing the editors not to upload broken geometries are things that > are very hard to accomplish. This leaves the third point and therefore > my question: > > Would the number of visible problems in the map due to dropping broken > geometries now, after the fixing effort, be low enough so this change > could be made to the main map to give mappers a better feedback about > broken geometries? Osm2pgsql is switching to the libosmium MP code which is more strict than the older code before. As far as I know the code is finished and should be in the next osm2pgsql version. Jochen -- Jochen Topf joc...@remote.org https://www.jochentopf.com/ +49-351-31778688 _______________________________________________ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
