About two weeks ago I asked a similar question on the Help Forum without
getting any help.
More precisely, my question was this
https://help.openstreetmap.org/questions/68275/coastline-as-part-of-a-multipolygon
.
Of course, the notes related to the example/illustration are fully correct but
have very little to do with the dilemma. I am convinced that this forum/list is
much more appropriate to repeat the former question in the link. Some more
arguments.
Users, like me, when processing the OSM source data, we see a large/huge number
of cases where coastline objects are used as parts of other object types like
lakes, rivers, fiords, sees, borders and so on. The large number of cases
indicate that this is more a practice now than accident. In my opinion a (very)
wrong practice. Let me present some illustrative arguments.
-There is still a large number of small coastline polygons inside the coastline
defined continents. As discussed many times, these coastline errors are
actually missing islands in lakes, or rivers or even missing lakes. Just
recently, many mappers compensate for these missing objects by uploading area
objects like place=island/islet, or lake directly referring to a coastline
geometry. So, we get coastline objects in none coastline objects. It is worth
noting that even if in some maps these compensations look correct, essentially
it is still wrong. A standalone coastline object tagged as place=island is
never part of a river or lake data. Very similar issues happen with the large
number of natural=land objects.
-Many of us remember the confusion created with bay/fiord area objects.
Especially when rendering of these was a requirement. Creating a large bay
object is not a simple exercise. These objects often contain thousands of
holes/islands and then it is easy ti miss some hundreds. The prototype example
of the confusion was the Bothnia bay. Lacily, someone with a strong sense
simply removed the whole bay object. However, there are still many other large
bay area objects, probably ignored by most of the map-makers in rendering. Yet,
these objects add huge redundancy to the source data.
-Finally, the crown example of the unreasonable “coastline in other objects” is
the recently uploaded/edited Barents Sea. It is a multipolygon monster tagged
as place=sea somewhere here
https://www.openstreetmap.org/relation/9382300#map=4/77.15/39.29
Any trials to see this object or its geometry in OSM maps (usually I check some
40) fails on my (really) robust machine. But then, what was the intention, the
purpose, of creating and uploading such a monster object. Just to see the name
variations and have a Wikipedia link? I am not sure whether the geometry
definition in this object is legal or not but anyway it just adds a huge
redundancy to the source data.
In advance thanks for the help/answer, Sandor
Sent from Mail for Windows 10
___
dev mailing list
dev@openstreetmap.org
https://lists.openstreetmap.org/listinfo/dev
