Hello 2018-05-16 10:01 GMT+03:00 SandorS wrote: > The statement was not quite wise and in some aspects it is wrong. Blindly > trusting open source solutions is not the best thing for a newcomer > especially not for a developer. By experience I know that sometimes a hint, > a simple warning may help a developer to change his way of thinking. > Besides, reading someone’s complex and complicated source (like the > generalisation related source) is not just a simple exercise. If you ever > wrote a complex basic sw and tried to read it after several months of brake > then you understand what is my point.
I think there was some misunderstanding here. I only stated that using commercial (or to be more precise - closed) software in my opinion is not the way to go for an open project like OSM. Results of generalisation using commercial software can be used to refine the approach (by looking, comparing), but final software will probably be open (and open gis software is gaining fast anyway). For example Netherlands example of using commercial software shows that generalisation is successfully(?) done on PARTS of data, so now we know that we do not have to think of ways to generalise whole world at once. Open data entered by volunteers does have a higher probability of errors, but generalisation could be just one of many ways of detecting such errors (and so fixing them). Regarding other points. There are a lot of different operations done on a lot of different types of objects in different sequences. But in my opinion it is not "all or nothing". You can start with some generalisation and progress with time. For example doing simple polygon aggregation/amalgamation is doable now with good results but should of course be improved with proper polygon conflict resolution methods (already described in numerous scientific papers, f.e. "Detecting and resolving size and proximity conflicts in the generalization of polygonal maps", Bader and Weibel 1997). Transport network collapsing (multi-lines to one line) can already be done with standard PostGIS functions (buffer, approximatemedialaxis). Building simplification is already in testing stage. GRASS provides functionality for transport network displacement and simplification/selection. And these already give good and noticeable results. Of course a lot of other things must be done, but we have a greatest luxury - time - there are no deadlines. This is why some operations could be implemented with even better results than closed implementations. -- Tomas _______________________________________________ dev mailing list firstname.lastname@example.org https://lists.openstreetmap.org/listinfo/dev