Now I see you said that the direction is not necesarry. I can't agree with this, it's a pretty important fact.
Anyway, I don't see a problem with you just importing incomplete data and waiting for someone else down the line to complete the ways inside areas. Janko. uto, 14. tra 2015. 11:48 Janko Mihelić <jan...@gmail.com> je napisao: > How do you know the direction of water flow if you don't have the way? > > Janko > > uto, 14. tra 2015. 11:45 Torstein Ingebrigtsen Bø <torstein...@gmail.com> > je napisao: > >> Hi, >> >> I'm currently importing topological data of Norway to OSM. From the data >> set we have riverbanks; however, we do not have the deepest middle way as >> required by the wiki [1]. This middle line is therefore drawn manually. >> This is a time consuming (and dull) job. For one municipal it takes around >> 5-10 hours to draw all these lines, in Norway we have 428 municipals. >> Drawing all these middle lines will slow down the time to import everything >> dramatical. I am therefore curious of what is the benefits of this line. Is >> it really necessary or is it a "nice to have"? >> >> Some disadvantages with this middle way are: >> - The line add redundancy. I guess that many add this line such that it >> is inside the multipolygon of the riverbank. Doing so the added data is >> only the direction of the river. (Other tags may be added to the >> multipolygon.) >> - Sometimes people draw the line wrong or forget to update it when >> updating the multipolygon. I have seen "middle" lines outside of the >> multipolygon (either inside islands or outside of the multipolygon). This >> gives false islands and splitting of islands when rendered. >> - A similar way can be generated, if direction and deepest point is not >> required. This comes as a fact of the first point and removes the >> previously mentioned problem. >> - For routing purposes this is not needed. (I have not seen any practical >> marine navigation/routing implementations yet, either.) Routing algorithms >> may also represent a riverbank as a node (or multiple nodes). The same >> problem occurs for lakes where it is not required to have a middle way for >> routing. >> - The direction of the river is seldom used. The direction of a river is >> seldom (or never?) rendered in any map. It is implicitly shown (e.g., by >> contour lines). >> - Specifically for the import of Kartverket N50 [2], this requirement is >> slowing down the import process dramatical and import of other data of more >> current value are delayed. This is therefore also a question of >> prioritizing data to be imported. >> >> I therefore propose to make this middle way in riverbanks recommended >> (when the deepest way is known), not required. >> >> [1] http://wiki.openstreetmap.org/wiki/Tag:waterway%3Driverbank >> <http://wiki.openstreetmap.org/wiki/Tag:waterway%3Driverbank#Old_tagging> >> [2] >> https://wiki.openstreetmap.org/wiki/Import/Catalogue/N50_import_(Norway) >> >> Best regards, >> Torstein I. Bø >> tibnor >> _______________________________________________ >> Tagging mailing list >> Tagging@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/tagging >> >
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