There seems to be quite a lot of anger and animosity in here - paired and in 
parts probably caused by a very selective and in parts flat out wrong 
perception of history so i will try to sketch quickly how the development of 
mapping of names of parts of waterbodies (that is mostly bays and straits) in 
OSM developed historically.

For a long time - until a few years back - these features were overwhelmingly 
mapped with nodes.  This was consensus, not because of technical constraints 
disallowing something else, but because of the realization that in the vast 
majority of cases this is perfectly sufficient to document all verifiable 
information available about the feature in question.  Practically in 2016 there 
were about 5 percent of all bay features mapped with polygons:

which - generously estimated - probably matches about the percentage of cases 
where you could argue that with a polygon you could record some verifiable 
information that cannot recorded with a node or a linear way (which still does 
not mean the polygon is a good data model for such features, just that it has 
in those cases - besides all disadvantages - also some advantages over a node 
or a linear way).

This situation was relatively stable - there were some attempts to suggest 
universally mapping bays with polygons rather than nodes previously:

which however never reached consensus because of the weighty arguments against 
this idea and because it was always clear that this would be a non-sustainable 
strategy for OSM in the long term.

Until early 2018 when OSM-Carto (where merging changes was at that time 
possible without consensus) added rendering of labels for bay polygons with 
label size and starting zoom level being determined by the size of the polygon 
but otherwise with no visual feedback or consideration for the geometry of the 

- dismissing warnings about the counterproductive incentives this creates:

This lead to a massive change in mapping activities with some mappers engaging 
in systematic endeavors of removing bay nodes and  drawing labeling polygons 
instead.  You can probably say this was by far the most successful attempt at 
steering mappers into a certain direction ever undertaken by OSM-Carto.  While 
the relative number of bay polygons compared to nodes only increased from about 
5 to 15 percent while very few bays were actually newly mapped the total 
surface area of bay polygons probably increased by a factor of 100-1000 - many 
of them evidently pure labeling geometries.  See

for some examples.  This has lead to some mappers removing such label geometry 
drawings as non-verifiable and pointless (like the mentioned Gulf of Bothnia) - 
though practically none of these attempts could make a dent against the massive 
labeling polygon drawing trends.

What does this have to do with technical limitations or constraints?  Very 
little.  Technical limitations and performance constraints in rendering have 
never been a factor speaking against drawing large and non-verifiable labeling 
polygons.  OSM-Carto and countless other map styles have for many years labeled 
huge administrative boundary relations without issues and this is not any more 
difficult for bay polygons.  And if it was an issue the solution would be 
rather simple:  Precalculating ST_PointOnSurface() on import in osm2pgsql.

The argument against drawing bay and strait polygons is one of practical 
verifiability and maintainability for the mapper.  This is not a technical 
issue, this is a social issue.  

Now i completely get the frustration of both mappers and map producers here.  
Mappers want their mapping to be shown in good quality in maps and if the only 
way to achieve that is to draw non-verifiable labeling geometries they are 
willing to invest significant time and energy into that and rationalize that in 
various ways.

And for map producers with a rudimentary GIS data analyst background and 
experience mostly in more or less atomic processing of point, linestring and 
polygon geometries and their spatial relationships but no deeper background in 
cartographic data processing specifically, the task of producing high quality 
labeling from bay nodes and a flat set of coastline ways or the osmcoastline 
output is a steep hurdle.  And in conventional digital map production from 
dedicated cartographic databases (in contrast to OSM with its generic 
geodatabase scope) labeling polygons is the state of the art to manage labeling 
of course.

The problem we have here is that of a widening gap between the goals and 
aspirations of the mapper community - which naturally grow as OSM grows in 
ambitions - and the abilities and engagement in the non-mapping part of the 
community to develop and satisfy similar ambitions in cartographic quality 
without outsourcing the hard part of that work to the mappers.  Too many people 
have followed the illusion for too long that the large corporate OSM data users 
will provide the necessary support in that field while it turns out 
(non-surprisingly in my eyes) that they have neither an interest in above 
average cartographic quality nor in substantially sharing methods and 
competency in the little work they do in that domain.

Christoph Hormann

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