[Talk-GB] Coastline and tidal rivers

[Colin Smale]

On 2018-09-02 10:50, Warin wrote:

> On 29/08/18 01:46, Colin Smale wrote: 
> 
> On 2018-08-28 16:43, David Groom wrote: 
> whilst in theory I'd say yes, in practice I'd say consensus is hard to achieve. 
> OK, I might as well give up now then. If everybody started thinking "I don't know why I bother," like I am now, where would we be?

To Colin I say in a loud voice ... "Up the Rebels" :) 

Thanks for the support...

> On the Australian talk list this came up for an import or maritime boundaries -note the last bits 
> 
> _Geoscience Australia definitions:_
> 
> * _"The __Normal baseline__ corresponds with the low water line along the coast, including the coasts of islands. Under the Convention, normal baseline can be drawn around low tide elevations which are defined as naturally formed areas of land surrounded by and above water at low tide but submerged at high tide, provided they are wholly or partly within 12 nautical miles of the coast. For Australian purposes, normal baseline corresponds to the level of __Lowest Astronomical Tide (LAT) [1]__._
> * _Straight baselines__ are a system of straight lines joining specified or discrete points on the low-water line, usually known as straight baseline end points. These may be used in localities where the coastline is deeply indented and cut into, or where there is a fringe of islands along the coast in its immediate vicinity._
> * _Bay or river closing lines__ are straight lines drawn between the respective low-water marks of the natural entrance points of bays or rivers._
> 
> _Waters on the landward side of the baseline are internal waters for the purposes of international law."_ 
> 
> Probably this same distinction exists in the UK - that difference of internal waters for international law. This may help achieve a 'consensus'?

The baseline is not the same as the coastline. 

The Coastline is: 

 	* A geographic concept delimiting the dry bit from the damp and wet
bits
 	* Based on high water mark

The Baseline is: 

 	* A legal concept, used as the basis for jurisdiction over territorial
waters etc
 	* Based on low water mark, with international rules for handling bays,
coastal islands, inlets etc

What you are referencing in Australia is the Baseline and it certainly
exists in the UK, but AFAIK it is not represented directly in OSM. The
12nm territorial waters limit which should be derived from the baseline
is however present in OSM. 

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Links:
------
[1]
http://www.ga.gov.au/scientific-topics/marine/jurisdiction/maritime-boundaries
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