[OSM-talk] Creating a multipolygon encompassing Black Sea

[Christoph Hormann]

On Saturday 19 June 2021, mappinglander wrote:
> I actually thought about creating a multipolygon for Black Sea, for
> helping to data consumers and therefore visualizing more easily by
> creating a multipolygon for Black Sea, which is currently tagged as a
> node at https://www.openstreetmap.org/node/7015642404

Small but important correction here:  A giant multipolygon for the Black 
Sea is not technically easier for data visualization applications than 
a node in combination with the coastline.  Just ask Jochen how 
complicated it is to reliably assemble multipolygon geometries.  Your 
assumption of this being easier is based on the fact that well tested 
and reliably working open source implementations for this task exist in 
common tools for OSM data processing while no similar implementations 
exist so far for visualizing such features based on nodes and costline.  
But it can be demonstrated that this is possible and does not impose 
significant difficulties, i for example showed it here:

https://media.ccc.de/v/fossgis2020-3126-weniger-ist-mehr-zur-auswahl-darzustellender-elemente-in-der-digitalen-kartographie#t=980

> [...] About naming, I am
> going to follow the same convention done at Caspian Sea: putting a
> name that encompasses all of the official languages of countries
> neighbouring to Black Sea. [...]

Note if it was fully up to me i would probably deliberately not show 
labels for any features that evidently contain something other than a 
single name in the name tag in OSM-Carto.  Such strings in the name tag 
abuse that tag as a label tag for the purpose of manually designing the 
label to be shown in maps instead of mapping verifiable names.  This 
does enormeous damage to the data in OSM - no data users can assume any 
more these days that the name tag actually contains the local name of 
the feature in question and you need fairly complex heuristrics to 
determine if it actually does.

Of course having a Black Sea label actually show up in OSM-Carto would 
also require you to mistag it either as natural=water or natural=bay.

-- 
Christoph Hormann
https://www.imagico.de/