[OSM-talk] waterways through water bodies

[Pierre Béland]

With a good river topology, it is possible to identify river basins. Note also that a new Wikipedia map functionality let's add map to wiki pages plus trace river paths from OSM river relations. 

See for example this 893km long river « La Grande Rivière » 
OSM relation    https://www.openstreetmap.org/relation/12523071Wikipedia map https://fr.wikipedia.org/wiki/La_Grande_Rivi%C3%A8re#/map/0  



 
Pierre 
 

    Le mardi 22 juin 2021 12 h 43 min 55 s UTC−4, Michael Heißmeier <michael63 at digital-filestore.de> a écrit :  
 
  Hi Mike,
 
 I would consider it similar to mapping riverbanks. The OSM wiki has a page with some graphics on that topic: https://wiki.openstreetmap.org/wiki/Rivers
 Furthermore, https://wiki.openstreetmap.org/wiki/Tag:waterway%3Driver says:
 
 
Just as with highways, it is important that the topology of rivers is correct. That means, if you can go from one part of the river to an other part of the river via the water, there has to be a piece of waterway =* between them. This implies that a way tagged as waterway = river should not stop on the riverbank of another river, but should proceed to the central way of the other river.
 
 That clearly says that the waterway for the river is the important object which must continuously be present. In all cases I have seen so far rivers were mapped as passing through lakes without any additional tags. If someone wants to treat that portion of a river specially then it is possible by geometrical database queries to extract river lines within water areas.
 
 Michael
 
 
 
 Mike Thompson, 22.06.21 17:31:
  
 
 I was reviewing recent changes in my area, and I came upon this: https://www.openstreetmap.org/way/956078735 
  If there is a waterbody (natural=water + water=lake or pond), and a stream or river (waterway=river or stream) flows into and out of that body of water, should the waterway be continued through the body of water? 
  If yes, should the portion of the waterway that is inside the body of water have additional tagging indicating this fact? 
  Thanks, Mike
  
  
  
  
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