On 29/3/23 14:30, Andrew Harvey wrote:
On Wed, 29 Mar 2023 at 14:05, OSM via Talk-au
<talk-au@openstreetmap.org> wrote:
Since the coastline tag is also supposed to represent the high
water mark then I would say that they should be snapped together
(since they then represent the same feature - that is, the high
water mark). This would mean that the boundary data already in OSM
from the government basemaps would just be their own mapping of
the high water mark, and probably be less up to date or refined as
our own.
Exactly. So if anything we should be actively snapping them.
In Victoria, from a very interesting document "THECOAST AND THECADASTRE"
AReport for the Victorian Environmental Assessment Council August 2019"
Unfortunately it is a PDF download only .. and I cannot get a direct
link so search for the above "Victoria the Coast and the Cadastre"
I quote from here on from the document, I do recommend reading all of it
if your interested in these 'ambulatory boundaries'.
---------------------
Detail of the plan defining Cape Conran Coastal Park2.
The inland boundary follows geometrically well-defined lines, and is
fixed in position.
North of the inland boundary is freehold land.
The seaward boundary of the Park is ‘Low Water Mark’ and hence is
ambulatory.
South of the seaward boundary (i.e.Bass Strait) is unreserved Crown land.
Topographic features may move, and ambulatory boundaries may move in
response under the common law doctrine of accretion. The doctrine is
well established internationally, but has resulted in very little
Australian case law, so we have come to accept Surveyor Generals’
rulings as beingde factoexpressions of the common law.
TheLocal Government Act 1989, section 3(3A) states:
“if a boundary of a municipal district is described by reference to the
seacoast (regardless of whether it is referred to as the Sea shore or
the waters of the sea or a bay or in any other way) that boundary is to
be taken to be the line for the time being of the Low Water Mark on that
sea coast”.
the surveyed sea boundary is defined only at that date. The sea boundary
is still subject to change due to gradual and imperceptible movement.
The fundamental concepts
(snip)
1The legal boundary between tidal waters and adjacent land is the High
Water Mark (except where the sea boundary is otherwise defined).
(snip)
6Land below high water mark (or other sea boundary) belongs to the Crown....
-------------------------
There are statements about;
the high water mark being used for both private and 'public' land
the 'foreshore' being council land
The report suggest that climate change will make things difficult and
that the government should 'make changes'. My pessimism says that they
will make no changes until things get much worse.
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