[Tagging] natural=bay on areas

Andrew Harvey andrew.harvey4 at gmail.com
Tue Mar 28 12:47:45 UTC 2017


Initially I was concerned that by changing the tagging from
natural=water, water=bay to natural=bay that the whole bay would be
rendered as land since that's what the wiki suggests. I now see that
the same user changed the edges of the bay to be natural=coastline to
prevent this.

I'm agree now that it makes sense for the wiki to not recommend
filling bays as water since a bays is either part of the ocean or part
of some other waterbody like a river, lake, reservoir   etc.). A
natural=bay as an area can share a common boundary with the riverbank
like http://www.openstreetmap.org/way/483211748.

I'm not convinced that the inside here should be tagged as
natural=coastline, as it simply doesn't match the description of what
a coastline is. I think the solution here is to include botany bay and
other bays here as part of a waterbody.

On 28 March 2017 at 00:28, Christoph Hormann <osm at imagico.de> wrote:
> On Monday 27 March 2017, Andrew Harvey wrote:
>> > It is a bay of the Tasman Sea/Pacific Ocean.  Ecologically it is a
>> > fully
>>
>> maritime waterbody.
>>
>> What do you mean by "maritime waterbody"?
>
> A waterbody where plant and animal life matches or is close to that of
> the sea rather to that of a river or lake.

I think it's a grey area, it's not completely like a river, nor that
of the sea. But in this case, I'm not sure, what information do you
have that confirms this?

>> Botany Bay is unlike many conventional bays which are on the
>> coastline and part of the sea. You're right that these types of bays
>> are part of the sea and ocean, and other times they are part of a
>> river, but botany bay is really a river nor sea, if anything Botany
>> Bay sounds much more like an Esturary.
>> https://en.wikipedia.org/wiki/Estuary
>
> In OSM we have no separate tagging for estuaries, this would not make
> sense because it would just introduce yet another boundary problem
> (where the river turns into the esturary and where the esturary turns
> into the ocean).  An esturary is the transit of a river into the ocean.

That's exactly what botany bay is, a transit of a river into the ocean.

> If you consider the Botany Bay to be part of the esturary of Georges
> River you still have to decide where you place the coastline and if you
> place it below the bay you have to tag the bay waterway=riverbank or
> natural=water + water=river.  Creating a separate waterbody that is not
> part of the river but within the coastline is wrong in our current
> tagging scheme.

I don't have a problem with waterway=riverbank, as many parts of the
shoreline here are closer to a riverbank than a coastline. That's
probably the best solution here.

> Note in general the esturary of Georges River would be considered to
> start much further upstream, likely somewhere around here:
>
> https://www.openstreetmap.org/#map=15/-33.9765/151.0237
>
> at the transit from a meandering river to a ria
> (https://en.wikipedia.org/wiki/Ria).

Thanks for that link!

On 28 March 2017 at 06:48, Juan Pablo Tolosa Sanzana
<jptolosanzana at gmail.com> wrote:
> A maritime waterbody are all those waters under the influence of the tides.
> You can review article for natural=coastline. The coastline should be placed
> in the "high water mean spring":
> https://wiki.openstreetmap.org/wiki/Tag:natural%3Dcoastline

The wiki says "The natural=coastline tag is used to mark the mean high
water spring line along the coastline at the edge of the sea." The
last part is key. The tidal limit is way upstream at
http://www.openstreetmap.org/search?query=-33.9252261917%2C%20150.9283593270#map=15/-33.9252/150.9284
but since the coastline tag is only marking high water mark on the
coast (the boundary between sea and land), it shouldn't be used there.

> Botany Bay is part of the ocean, not a separate inland waterbody. You can
> see in the terrain the mark of the tides.

So you're saying that anything below the tidal limit is the ocean?

>> If you swim at a coastal beach you're swimming in the sea and the
>> ocean. At the beaches of Botany Bay, no one would say you're in the
>> sea or ocean. Nor would they say you're on the coast of Australia.
>
> This is only a colloquial thing. That lacks of verifiability. For example,
> Dead Sea is not a sea, really is a lake.

What's the verifiable thing on the ground which backs up
natural=coastline on the inside of the bay(s)?

>> Botany Bay is unlike many conventional bays which are on the coastline
>> and part of the sea. You're right that these types of bays are part of
>> the sea and ocean, and other times they are part of a river, but
>> botany bay is really a river nor sea, if anything Botany Bay sounds
>> much more like an Esturary. https://en.wikipedia.org/wiki/Estuary
>
> The rules for tagging are in the OSM wiki. Even in Wikipedia says Botany Bay
> is an oceanic bay: https://en.wikipedia.org/wiki/Botany_Bay
> The coastline is a natural feature. You don't mix it with political things.
> You can use the tag boundary=maritime + maritime=base_line to delineate
> political inner waters. Even the boundary runs in the mouth of Botany Bay,
> therefore is respected local things that you mean.

Yeah I'm not trying to tag political boundaries, or political maritime
boundaries. I just strongly feel that
http://www.openstreetmap.org/way/220111130 is not a coastline.

> Here there are instructions to tag an estuary:
> https://wiki.openstreetmap.org/wiki/Proposed_Features/Coastline-River_transit_placement

Thanks for that link, I'll take a read through that and make some
comments over there.



More information about the Tagging mailing list