On Thu, Sep 27, 2012 at 10:21:38PM +0100, THEVENON Julien wrote: > > De : Sarah Hoffmann <lon...@denofr.de> > > I don't know which data you have been looking at, but let's ask > Nominatim, shall we? > > Ok, so by example could you extract stats from Grenoble instead of whole > France ? I thinks this quite representative of cities where there are > buildings and quite a lot of details.
Grenoble (as in relation 80348) has 13199 raw buildings and 10160 other objects indexed. So, yes, this seems to be an example where the cadastre data was put to very good use. But the fact remains that this does not happen in most of the rest of France. The larger part of cadastre data is just dumped into the data base never to be touched again by any mapper. (For reference: for the entire planet there are approx. two other objects for each raw building. This ratio holds even for Germany.) > Concerning discussions about separated accounts I`m sure that there is a good > reason behind that but it was perhaps decided for cases that do not match > French one. What we are trying to do here is to discuss to understand why > this rule has been done ( that's why we are asking for a list of issues that > import Guidelines Rules want to address ) and if it is possible to find a > solution both satisfy the goal you have and that do not create problems for > good-will french mapppers that spend time to perform clean cadastre > integration. I`m convinced ( or at least I hope )that you don`t create this > rule to make French mappers crazy. The main problem is that you are asking for an exception to the import rules on the grounds that your imports are small and carefully manually checked and augmented with non-cadastre data. The numbers simply don't support your claims. In fact, they say that the cadastre import is the largest import OSM currently has to deal with, if it is not even the largest import OSM ever had to deal with. If the French community could admit that it would be a big step towards resolving the conflict. Nobody contests that the cadastre situation is special. There is no question that you have been thinking about this import very carefully. The amount of work you have put in the development of tools for it is admirable and you put a lot of effort into monitoring the progress, so it certainly is not completely dead data. Still, the amount of data you add is more than could be possibly ever looked over and amended by the French community. The Germans did have a bit of a head start and so far managed to 'only' add about 13 million objects to the database, half of what you have added in buildings. I do think that Richard's proposal presents a fair compromise for you. Those who only want to add a bit of data for their home town can do so without the hassle of creating a second account but those who import the data on a larger scale without the chance to ever check what they import locally must adhere to the import guidlines and do so on a special account. The barrier of entry that creates is not necessarily a bad thing. > Concerning the waste of bandwidth and CPU, the nuisance for people who want > to use OSM data I understand the problem but I guess it will come even > without cadastre because due to Open Data mouvment there will certainly more > and more big data sources to integrate. It it not really the amount of data that is the problem. There are ways to handle that. Storage does get cheaper with time. The problem is that the data, as it is today, is - excuse the hard word - garbage in the eyes of data users. You cannot use it for search or routing, there are no addresses or names or pois. It is rather ugly for rendering, there are no real buildings just unspecific building parts and way too much detail (small round edifices using up 40 nodes, what for?). You cannot do real statistics on them, there are just unspecific building parts... So essentially alomost every data user has to go through 25 million buildings just to throw them away. It is not the end of the world, but it is mildly annoying. cadastre could be a great resource for mappers if used responsibly. Restrict yourself to areas where you know that mappers will add more details immediately. If you really believe that importing the data attracts new mappers then make sure that the data is massively simplified before the import. You still have the source. If really in the future somebody wants to add information that require more detailed building outlines, you can go back to cadastre and get those details. If you could change your strategy in that way you would make the data infinitly more useful for data users and you would most likely find much less opposition in the international community against cadastre. Sarah _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
