[Tagging] Rio de la Plata edit war

Christoph Hormann osm at imagico.de
Mon Jan 13 11:39:15 UTC 2020

On Monday 13 January 2020, Frederik Ramm wrote:
> According to Wikipedia, the International Hydrographic Organization
> defines the eastern boundary of the Río de la Plata as "a line
> joining Punta del Este, Uruguay and Cabo San Antonio, Argentina",
> which is what has been the case in OSM until now:

That is a straw man argument that has been floated already at the very 
beginning when a riverbank polygon was first created for that (which 
was later than when the Río de la Plata was originally mapped by the 
way - just to clarify that).

The IHO specifies an (obviously subjective and non-verifiable) set of 
limits of *oceans and seas*.  If anyone wants to use this as an 
argument that would make the Río de la Plata a marginal sea of the 
Atlantic Ocean and therefore to be placed outside the coastline.  So 
using the IHO as a source (in lieu of the verifiable geography in a 
Wikipedia-like fashion so to speak) kind of defeats the basic argument 
for the Río de la Plata to not be a maritime waterbody.

> This current representation in OSM leads to a few strange situations
> especially in toolchains/map styles that use different colours for
> inland water and oceans, or that draw sea depths, or just highlight
> the coastline. Buenos Aires, according to OSM, is currently not a
> coastal city.

The main reason why the current mapping is vigorously maintained by some 
local mappers is political in nature.  Argentina and Uruguay want to 
claim this area as internal waters (and the administrative boundaries 
are mapped accordingly) but not every other nation accepts this claim.  
Presenting the Río de la Plata as a non-maritime waterbody in as many 
maps and data sets as possible would support such claim.

My own solution as a data user to this has been to simply maintain a 
coastline cheatfile which marks this as a special case and moves the 
Río de la Plata polygon into the ocean polygon data.  This is 
unfortunate but way simpler than trying to fight against a widespread 
politically motivated conviction.  See also:


> I'm not so clear about how to interpret the wiki page myself when it
> comes to river mouths. There's a clarifying proposal here
> https://wiki.openstreetmap.org/wiki/Proposed_Features/Coastline-River
>_transit_placement but this is still at the proposal stage.

The IMO logical approach to placing the closing segment of the coastline 
at a river mouth according to the spirit of the OpenStreetMap project 
is to place it where for the verifiable view of humans the maritime 
domain ends and the riverine domain starts.  This is largely an 
ecological question.  Coastline and riverbanks are physical geography 
features so their position is to be defined by physically observable 
characteristics rather than politically defined limits.  Like so often 
(for example in case of the line between scrubland and woodland) this 
is often not a clearly visible sharp line but a transit.  There are 
however clearly observable limits to the extent of this transit.  The 
proposal cited tries to specify those.

Back when i drafted the proposal there was very little interest in the 
subject except by those who were opposed to it for political reasons.  
Therefore i did not pursue it further.  But anyone is welcome to take 
it up again.

Christoph Hormann

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