[mkgmap-dev] nearby-POI: What to do with several POI arranged on a circle?From Ticker Berkin rwb-mkgmap at jagit.co.uk on Thu May 7 10:28:53 BST 2020
Hi Gerd The bench in lake problem is avoided by the user not using the merge-at -mid-point option. Possibly making the delete-poi option keep the most central one and delete the rest. Ticker On Thu, 2020-05-07 at 09:12 +0000, Gerd Petermann wrote: > Hi Ticker, > > I should have used amenity=bench in the example, this is a bit more > realistic, but the default style doesn't generate a POI for that. > > I've found a rather simple iterative algo to fix the problem, but > what I really wanted to point out is that the result can look really > wrong. > Benches are often arranged around something, e.g. a small lake/pond. > I think nobody wants a map that shows a bench in the middle of a > lake. > OTHO, bus stops typically come in pairs, but maybe 50m apart. It > seems reasonable to merge them in the middle. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag > von Ticker Berkin <rwb-mkgmap at jagit.co.uk> > Gesendet: Donnerstag, 7. Mai 2020 10:21 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] nearby-POI: What to do with several POI > arranged on a circle? > > Hi > > The problem is in the point grouping algo, rather than anything to do > with the merge-at-mid-point option. > > Although an interesting problem to solve, it seems to be getting > excessive. The simple logic in the last versions seemed to solve most > users's problems and make them happy. > > Ticker > > > On Thu, 2020-05-07 at 07:42 +0000, Gerd Petermann wrote: > > Hi all, > > > > while doing further tests I've found this edge case (see attached > > file) > > Draw a circle with a diameter of ~56m and tag all nodes > > amenity=bank. > > The default style has > > amenity=bank [0x2f06 resolution 24] > > > > With --nearby-poi-rules=0x2f06:30:merge-at-mid-point one might > > expect > > a single POI in the middle of the circle, but the result is > > different: > > Since there is no POI near the center of the circle the current > > algo > > finds 4 groups, all close to the edge of the circle. > > > > I think for merge-at-mid-point I need a different algo. I'm looking > > at https://en.wikipedia.org/wiki/Cluster_analysis now. > > > > Gerd > > > > > > > > _______________________________________________ > > mkgmap-dev mailing list > > mkgmap-dev at lists.mkgmap.org.uk > > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev at lists.mkgmap.org.uk > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev at lists.mkgmap.org.uk > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
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