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
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