[OSM-dev] Coastline as part of other object types?

[SandorS]

>>
>>Can you link some objects that you consider as tagged in a wrong way and
>>some similar ones tagged in way that you consider correct?
>>Currently it is unclear to me what is the problem.
>>
These notes have triggered my attention from the Re to my original mail. It is hard to communicate if you really don not see the problem, though I think you meant  something else. What more, whether the referenced issues are problems or not, depends on the individual criteria. Anyway, I need to add some notes and representative examples to clarify the dilemma: is the recent practice referencing coastline objects from other objects correct or not?
-Coastline object covered by a river https://osm.org/go/ZE6RWif_--?layers=T&way=22404175 . The object is in the coastline data erroneously left there when the other object has been moved out from the coastline data. This island in the river will never show up in the maps unless it is moved out from the coastline and added to the river data as a hole.
-Similar example here https://osm.org/go/0YQozaPCa?way=503202265 but with the additional tag place=island. If a renderer assumes in addition that this place is an area and renders the places it will properly show up un the map. But even then, the object is actually never part of the river object. All tags should be removed and the polygon should be moved to the river data as a hole.
-As I mentioned in the mail, we have similar issues here https://osm.org/go/55iNMeSpU-?layers=HD&way=482531057  with the natural=land objects. Even if it is declared deprecated many years ago this tag is still actively used and there is a large number of natural=land objects in the source data. Note that logically the suggestion to use the place=island tag instead is just an implicit reimplementation of the natural=land objects.
-There are also many coastline objects in lakes like here https://osm.org/go/JzzBB0Vmt--?layers=D&way=440616441 . The same comments are valid as in case of rivers. The question whether this object is a lake or river is something else. 
-A similar lake related example is here https://osm.org/go/e6GG5QpcE-?way=615864002 but the coastline object is perfectly declared as a hole in a lake. Still there might be a problem. The coastline tag will suggest that the object will primarily be processed in the context of Planet land masses. And, because it is land-on-land it might be easily removed from the coastline data. In the similar cases any tags should be removed except the inner tag.
-Finally, the major issue that has motivated me to start this discussion, the coastline referencing from objects like fiord/bay and sea. These, usually monster sized objects, are difficult to understand. Why, who is using them, what was the purpose to upload them? Even if someone uses them to see the name variations or read the linked Wikipedia texts, the price is very high. These objects add huge unnecessary data amount to the already enormous source data. I am afraid this practice will lead to a situation where handling of the Planet data will be a privilege only of some rich institutions. If you have tried to click the link, to see the Barents Sea object from my original mail, you understand my dilemma. And this sea is not an exception. There are many bays, seas uploaded as new place areas like this one https://osm.org/go/cjf3ZrG?layers=H&relation=9428957 from several days ago. Just try to click on the “+” button and/or on the sea multipolygon object. 
Sandor



  
 

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