I just tried out the simplify4 patch - it gives the best results so far. Overall this is really a huge improvement now for contourlines! Strangely also at resolution 24 there have been improvements (or is it changes?). Actually I wanted to try DP at resolution 24 but removing those lines that prevent it to run, and adding 24 * 1 into my patch, changed absolutely nothing. Maybe the newest simplify4 patch does DP for resolution 24 too?
Still at resolution 24 the contourlines with B-Spline from kleineisel vs phyghtmap look nicer - and I would guess are a little bit more correct - but mkgmap cannot improve data and gnuplot just seems to work better than phyghtmap. But from resolution 23 onwards it's exactly the opposite. My contourlines with simplify v4, DP at 1.3 and then according to my patch, look way way better in mountains. In flatter areas the differences are anyhow smaller. I'm still playing around a bit with values for the dp filter. The essential is to have lower values for 23 and 22 and higher after. For contourlines a lower value is needed IMHO than for maps - as contourlines look strange if they get straightened too much. Maybe partly due to the underlying data quality too. Compared to the current I feel for maps 23=3.6, 22=5.4, 21=8, 20and onwards 10.8 or so seems to work quite well. For contourlines 23=1.3, 22=2.6, 21=4, <=20=5.4 seems to work quite well. I think maybe move that into the options file so it doesn't clutter up the commandline too much. Now what to use default I find hard to say. Because without contourlines higher values do not cause problems visually. I have not toyed around with polygons. Polygons are a bit tougher anyhow maybe, if too high values create holes? On Fri, 30 Apr 2021 at 21:50, Gerd Petermann < gpetermann_muenc...@hotmail.com> wrote: > Hi all, > > attached is my proposed change based on the simplify3.patch by Andrzej and > the idea to use that only for contour lines. > > I see no simple way to implement major improvements for the rendering of > lower resolutions. Basically we need the WrongAngleFixer to work with a > given resolution. > So, something like a loop over each level (starting with the highest) > + collect the elements that should be rendered at this level > + use method like WrongAngleFixer for the corresponding resolution so that > distortions caused by rounding are reduced > + add code to detect parallel lines which should be deduplicated > + store the objects, each only valid for this one level > > Finally do the sub division splitting, the merging of lines and shapes in > each sub div and the binary encoding of the map. > If possible, the merging and the Douglas-Peucker-Filter (or whatever) > should be done before splitting into sub divs. I assume Garmins program is > doing it that way because the data structures suggest that they fist > calculate all the elements of all levels before it starts the splitting > into sub divs. > > I guess this would produce nicer looking maps at lower resolutions. It > would also require more heap memory (100% would be my guess) and more > compilation time unless we find clever tricks to avoid that. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk> im Auftrag von > Felix Hartmann <extremecar...@gmail.com> > Gesendet: Donnerstag, 29. April 2021 14:39 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution > 23 raster problems > > here is what I mean - zig zagging like crazy if you look at it with lowest > detail which is really helpful to see this problem. Those highways should > be just straight. Oh yes - because the highways are two separate lanes they > never have holes. Those holes with the patch are best visible on highway > primary and secondary. Actually for highways maybe mkgmap could even > include an algo to fix the double highway and just put it once into the map > if it overlaps. So step a) remove zig zagging. Step two - remove any double > highway if within 3-4 garmin units away from each other as long as we do > not create a hole by this (at intersections). Every style has minimum width > for highways of at least 3-4 units, if not 6-7, so drawing two highways on > top of each other is waste of resources. Actually this applies to all > roads but will be mainly important for highways as they are nearly always > entered into OSM with both directions as a separate line. > > On Thu, 29 Apr 2021 at 20:30, Felix Hartmann <extremecar...@gmail.com > <mailto:extremecar...@gmail.com>> wrote: > Yes - I also support Gerd that it doesn't work well for polygons. > Now for lines it's another story. > a) I love that lines are a bit straighter and looking better vs increasing > douglas peucker. > b) Sadly though there are bits and pieces of roads missing. If that is > fixed I would be all supportive to use this for all lines. But not before > those missing bits reappear. > How to check for it - just use lowest detail level in Basecamp. > > Oh yeah and mkgmap without that patch also has a zig zagging problem. > Maybe we would need a separate algorithm to check for zig zagging and make > sure this does not happen. I really think we could need an algorithm that > just checks for zig zagging from resolution 22 and lower and base it on the > principle that 90% of all those zig zags are unwanted therefore just > straighten lines if there is a zig zag. > So nothing to do with this patch - but a general really needed improvement > for mkgmap. (mkgmap is lacking a bit vs Garmin owns map at lower > resolutions. At resolution 24 mkgmap produces fantastic maps, but garmins > own maps are definitely better at lower resolutions regarding problems like > zig zagging or reducing detail). Avoiding those zig zags would make the > maps pan and load much faster on devices. I use a high DP value of 5.4 > because zoomed out further I feel this is needed. But the zig zagging > occurs anyhow, or because of it? > > I really feel some little tweaks here could be a huge improvement for > practical use on devices. We do not need exactness when zoomed out far - > but we need the map to look nice. If a line is 1 or 2 points away from > reality doesn't matter from resolution 17-21 and matters not too much for > resolution 22. Only 23 and 24 should be more or less exact. (maybe for > driving on highways with a car this is different - but is anyone actually > using mkgmap created maps for this? I think nearly everyone uses google > maps or smartphone. Garmin maps are mainly for outdoors or city maybe. But > not for automobile use. Some people but not many motorcycle maybe. So the > main importance for lower resolution is nice visual display and fast, not > if a road misses some tiny turn or is 100m left or right. And with a car we > have lock on road exactly for that. So visually it will be on the road > anyhow even if the road is moved 1 or 2 garmin units to one side. > > On Wed, 28 Apr 2021 at 22:59, Gerd Petermann < > gpetermann_muenc...@hotmail.com<mailto:gpetermann_muenc...@hotmail.com>> > wrote: > Hi all, > > my observations at resolution 22: > I think the patch re-introduces rendering problems at T-shaped crossings, > sometimes they look like t-shapes at lower resolutions. > Sample: https://www.openstreetmap.org/node/260418111 > > It seems to filter more small polygons, even with --min-size-polygon=0. > I think it tends to make polygons smaller, not sure why. > > It sometimes reduces wrong zig-zagging, but only for ways with many > points. In cities, where roads are often split into many small parts it > sometimes makes things worse. > > It probably helps for the special case contour lines and therefore I > suggest to limit it to them. > > Maybe the code to find the best place for a rounded coord should also > consider to remove the point if that would give the best result. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk<mailto: > mkgmap-dev-boun...@lists.mkgmap.org.uk>> im Auftrag von Gerd Petermann < > gpetermann_muenc...@hotmail.com<mailto:gpetermann_muenc...@hotmail.com>> > Gesendet: Mittwoch, 28. April 2021 15:21 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution > 23 raster problems > > Hi Felix, > > I expect (more) small missing parts of complex shapes like forests or > waterway areas (those without mkgmap:skipSizeFilter=true) and more obvious > differences between shapes and lines, e.g. if a style renders outlines of > buildings. > > The maps are very different at res 22, so it is hard to say if there are > more improvements then worsenings. > > I've experimented with different orders of filters in the past. It's > difficult to test because the changes heavily depend on the Styte AND the > mapped objects AND the mappers preferences. For example, if landuse areas > are glued to highways or not, if landuse areas are glued to other landuse > areas or if there nodes are just very close. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk<mailto: > mkgmap-dev-boun...@lists.mkgmap.org.uk>> im Auftrag von Felix Hartmann < > extremecar...@gmail.com<mailto:extremecar...@gmail.com>> > Gesendet: Mittwoch, 28. April 2021 14:58 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution > 23 raster problems > > Oh I thought it was mainly meant for contourlines. Did not know you intend > it to be used in general. I am not really sure how and where to check for > quality. > > On Wed, 28 Apr 2021 at 20:13, Gerd Petermann < > gpetermann_muenc...@hotmail.com<mailto:gpetermann_muenc...@hotmail.com > ><mailto:gpetermann_muenc...@hotmail.com<mailto: > gpetermann_muenc...@hotmail.com>>> wrote: > Hi Felix, > > your screen shots only show contour lines but the patch works on all types > of lines and polygons. So, please also check the results with other maps. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk<mailto: > mkgmap-dev-boun...@lists.mkgmap.org.uk><mailto: > mkgmap-dev-boun...@lists.mkgmap.org.uk<mailto: > mkgmap-dev-boun...@lists.mkgmap.org.uk>>> im Auftrag von Felix Hartmann < > extremecar...@gmail.com<mailto:extremecar...@gmail.com><mailto: > extremecar...@gmail.com<mailto:extremecar...@gmail.com>>> > Gesendet: Mittwoch, 28. April 2021 04:54 > An: Development list for mkgmap; Andrzej Popowski > Betreff: Re: [mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution > 23 raster problems > > forgot 1.3 value - that is good enough (and this location is not the most > difficult, but there are very few places that are worse. So I feel it's > good enough as if it's fine here - there are very very few other places > that are still problematic. > > > On Wed, 28 Apr 2021 at 10:50, Felix Hartmann <extremecar...@gmail.com > <mailto:extremecar...@gmail.com><mailto:extremecar...@gmail.com<mailto: > extremecar...@gmail.com>><mailto:extremecar...@gmail.com<mailto: > extremecar...@gmail.com><mailto:extremecar...@gmail.com<mailto: > extremecar...@gmail.com>>>> wrote: > Thanks for that patch, the improvement is not as big as from the previous > patch - but there is some. > I analysed it a bit more - and I think there needs to be one more change - > actually in general and not only for contourlines. > > We need different values for the douglas peucker algorithm depending on > resolution! > > Right now we can only set one value, and that is multiplied for each > resolution? > Based on the current state I would like to have > > resolution > 24= 0.0 or maybe actually have it active at 24 as well trying a value of > 0.3 or so. Where there any problems with autorouting or why is it not > possible to use it at resolution 24 as well? > 23=1.3 > 22=2.6 > 21=3.9 > 20-11=5.4 > > > Especially if we produce a map without resolution 24, then resolution 23 > needs to have much lower DP value than the subsequent resolutions. Using > 1.3 for resolution 23 makes the quality IMHO good enough to be used for an > contourlines only map for GPS devices and skipping resolution 24 > altogether. For Desktop use resolution 24 may still make sense for > contourlines - but even then the difference is only in very steep areas. > > Attached some screenshots at resolution 24, and at 23 with different DP > values and one of patch2. > > On Tue, 27 Apr 2021 at 23:16, Andrzej Popowski <po...@poczta.onet.pl > <mailto:po...@poczta.onet.pl><mailto:po...@poczta.onet.pl<mailto: > po...@poczta.onet.pl>><mailto:po...@poczta.onet.pl<mailto: > po...@poczta.onet.pl><mailto:po...@poczta.onet.pl<mailto: > po...@poczta.onet.pl>>>> wrote: > Hi, > > some more experiments, see attached patch. I have tried to optimize > rounding of coordinates for lowest distance to line. This is not good > for polygons, because can creates gaps between adjacent polygons. > > -- > Best regards, > Andrzej > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk<mailto:mkgmap-dev@lists.mkgmap.org.uk > ><mailto:mkgmap-dev@lists.mkgmap.org.uk<mailto: > mkgmap-dev@lists.mkgmap.org.uk>><mailto:mkgmap-dev@lists.mkgmap.org.uk > <mailto:mkgmap-dev@lists.mkgmap.org.uk><mailto: > mkgmap-dev@lists.mkgmap.org.uk<mailto:mkgmap-dev@lists.mkgmap.org.uk>>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk<mailto:mkgmap-dev@lists.mkgmap.org.uk > ><mailto:mkgmap-dev@lists.mkgmap.org.uk<mailto: > mkgmap-dev@lists.mkgmap.org.uk>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk<mailto:mkgmap-dev@lists.mkgmap.org.uk> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk<mailto:mkgmap-dev@lists.mkgmap.org.uk> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev -- Felix Hartman - Openmtbmap.org & VeloMap.org
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