On Sat, Feb 18, 2017 at 07:50:07AM +0100, Oleksiy Muzalyev wrote: > On 15.02.17 23:51, Sarah Hoffmann wrote: > > ... we are > > currently discussing about changing the algorithm that assembles the > > polygons[1]. The new algorithms will be a lot faster but that comes > > at the price that it is less tolerant with invalid geometries. A lot > > of bad geometries that are currently still drawn some way or another > > will be simply dropped. I'm convinced that in the long run this > > stricter handling will be good not only for data consumers but also > > for mappers, who will see immediately when they made a mistake. > > ... > > > Hi, > It would be a good idea to generate automatically a message to an author or > authors of this geometry asking them to fix it, explaining shortly what an > error they committed, and informing them that it would be deleted, if they > do not fix it. And if there is no reaction after a tolerance period of say > one week, then drop it automatically.
Most multipolygons we are talking about here haven't been touched in years. So this doesn't really apply. Most of this is about cleaning up the backlog. If you look at the stats on http://area.jochentopf.com/stats/ you'll see that the number of (multi)polygons is growing constantly, but the number of errors is not. This tells me that it is mostly a problem with old data. We could inform authors when new problems are coming up, but I suspect that this is very difficult. For one, there can be several people involved and you don't know which fault is was. Then there is the question of what to tell the user. If you send them an email "Your multipolygon id 1234567 is broken", that is not very helpful for them. We need at a minimum some guidance on how to fix things. But this depends at least on the editor used, the language of the user, the type of problem and the skill level of the user. Ugh. > Deleting objects from the map without a warning may cause suspicions and > misunderstanding. For example, there are areas mapped as > boundary=protected_area or landuse=nature_reserve , but local fishermen who > want to continue fishing in the area may not like it, or at least have > doubts about its shape. By deleting a Nature Reserve from the map the script > may inadvertently interfere into a balance situation. This is why we are having this discussion. We do not want to remove anything from the map lightly. We are doing this only after taking any measure we can to fix those cases. In the long run the situation will get better, because at the moment some of those "critical" polygons you are talking about might not show up or show up wrong on the map because of the errors they contain that the renderer is trying to fix and doing so in the wrong way. We are doing all this to improve the accuracy of the map! 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
