[Tagging] Coastline for rivers, estuaries and mangroves?

Joseph Eisenberg joseph.eisenberg at gmail.com
Mon Sep 10 00:09:34 UTC 2018

The legal definition of the baseline is the low tide line and also cuts
across bays, inlets and estuaries.

But OSM has always marked the coastline at the mean high water line, and
that is also the line shown on most maps. It is also much easier to verify
than the low water baseline, which by definition is in the sea 99% of the

I believe the German language Wiki page mentions that the baseline can be
marked as an administrative boundary, because it is a legal fiction, not a
geographical feature of the landscape.

In the past a few people have mentioned adding the low water line as a
second feature in addition to the coastline, but so far people have beeen
individually drawing shoals, mud flats, beaches and other wetlands befoyond
the coastline, which seems sufficient to me.

On Mon, Sep 10, 2018 at 8:31 AM Graeme Fitzpatrick <graemefitz1 at gmail.com>

> On Mon, 10 Sep 2018 at 08:25, Colin Smale <colin.smale at xs4all.nl> wrote:
>> So are we getting any closer to consensus on where the coastline should
>> cross the river? I think only if it is "somewhere between the tidal limit
>> and the sea". Are all "crossing points" then equally valid? Or can we
>> expect strong disagreements (especially at the limits) and possible edit
>> wars?
> Unfortunately, I don't think we are ever all going to agree - some people
> are adamant about the tidal limit, while other's are equally convinced that
> it should be where the river enters the sea, & both arguments are just as
> logical as the other.
> I think part of the problem is the lack of a precise definition of just
> what is the "coastline"? eg Merriam-Webster dictionary "a line that forms
> the boundary between the land and the ocean or a lake" which could well
> mean that the coastline goes up a river, but how far?
> While searching for a better answer, I did however find this:
> http://www.myfloridalegal.com/ago.nsf/Opinions/E2D8E00068ACF5EE8525622F004AA168
> .
> Some of the highlights include:
> "Congress reacted to these decisions by enacting the Submerged Lands Act
> of 1953.[10] Congress defined "coast line" to mean "the line of ordinary
> low water along that portion of the coast which is in direct contact with
> the open sea and the line marking the seaward limit of inland waters"
> "the Supreme Court set the meaning of "coast line" in its earlier
> decree.[32] The Court defined the term to mean "the line of ordinary low
> water along that portion of the coast which is in direct contact with the
> open sea and the line marking the seaward limits of inland waters.""
> "During the late 1950s, the coastal countries of the world proposed,
> discussed, and drafted a treaty known as the Convention on the Territorial
> Sea and Contiguous Zone, April 29, 1958.[34] The hope was to provide
> uniformity in the delineation of the nations' territorial sea. Rather than
> using the term "coast line," the Convention used the term "baseline" in the
> measurement of the territorial sea. Article 3 defines the "baseline" for
> measuring the territorial sea as "the low water line along the coast as
> marked on large-scale charts officially recognized by the coastal State."
> The Convention was ratified by the United States in 1961 and became
> effective in 1964.[35] It is as a result of the Convention that the term
> "baseline" is used regarding coastline issues."
> "By applying both the Convention and the Submerged Lands Act to Article
> X, section 16, Florida Constitution, the following results:
> "A. 'Coastline' is the low water line that meets the shore along the coast
> of Florida which is in direct contact with the open sea. A coastline can
> never begin in open water; a coastline, in plain terms, is where the water
> meets the land."
> Now, I would interpret all that as meaning that coastline & baseline are
> the same thing, so that the coastline should follow the line of the coast,
> cutting across the mouth of any rivers?
> Thanks
> Graeme
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