[Tagging] Layers

[Kevin Kenny]

On Wed, Sep 7, 2022 at 3:58 AM Marc_marc <marc_marc at mailo.com> wrote:

> Hello,
>
> Le 07.09.22 à 03:05, Kevin Kenny a écrit :
> > When natural features move, the law gets complicated, because accretion,
> > erosion, avulsion, reliction, and so on all are distinct cases in the
> law.
>
> you just have to define the members of the relationship correctly:
> if the boundary is the middle of the river and moves if the river moves,
> then you have to put the end of this river in the relation.
>

OSM is not a court of law.  A major change to a watercourse will usually
result in an indefinite boundary and a future lawsuit.


> if the river passes at this place without following the future
> evolutions of the river, then one should not include the river in
> relation but make a new object.
>

A particular event that moves a river may or may not move a boundary - and
it's impossible to determine in advance what sort of event will occur.
Gradual erosion and accretion is handled as a different case in the law
from an event where a sudden catastrophe changes the course of a river.
This difference is almost universal in Common Law countries (most of the
English-speaking world).  Countries whose legal code is founded on Roman or
Napoleonic law likely have different rules.

Because of the future uncertainty, working as I do in the US, I do _not_
ordinarily glue boundaries to watercourses. All the cases I've raised as
examples are ones where I've done the historical research and have a fair
idea what's what. (And I'm glad I don't do this sort of stuff for a living!)

a description tag would help a lot to keep this information but it is in
> my opinion a titanic work to find the definition of many borders
>

I tend to depend on the 'authoritative' data from the taxing authorities;
they have a financial interest in determining how much land area their
borders encompass.

In a lot of New York, boundaries simply are indefinite, and even the USGS
topo maps recognize the fact.  Note at
https://caltopo.com/map.html#ll=44.12372,-74.23209&z=15&b=t not only the
words, "INDEFINITE BOUNDARY" but also the error of closure!

-- 
73 de ke9tv/2, Kevin
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