[Tagging] Other missing landform tags

Joseph Eisenberg joseph.eisenberg at gmail.com
Sun Apr 21 14:38:07 UTC 2019


On 4/21/19, Warin <61sundowner at gmail.com> wrote:
> Arch = A hole though some feature, usually rock. Covered overhead and to
> both sides, open at both ends.

This is natural=arch
https://wiki.openstreetmap.org/wiki/Proposed_features/Natural_arch -
as mentioned by Paul Allen above

> archipelago = an island group or island chain

place=archipelago - I recently updated this page but it's been in use
since 2013 https://wiki.openstreetmap.org/wiki/Tag:place%3Darchipelago

> basin = The tract of country drained by a river and its tributaries, or
> which drains into a particular lake or area. Note need to be careful not to
> confuse this with man_made=basin or sea basins.

I asked about this a few months ago. Several people were against
mapping drainage basins, because the verifiable boundaries can be
mapped as natural=ridge, and the others are not verifiable.

> Canyon: A gorge, relatively narrow but of considerable size ...(possibly tag as gorge with
> gorge=canyon?)

The alternative, already suggested on some non-English pages, would be
natural=canyon - used 163 times; or natural=valley with valley=canyon?
I would map these as a node or as a linear way that follows the low
ground or the waterway

> Cap = ???

Misspelling for cape? Or a type of peak? No idea.

> Col or gap (use saddle? And that is in OSM) = a col is the lowest point on a
> mountain ridge between two peaks.

Yes, "col" is the French word for saddle, a low point on a ridge.

A gap is also usually a saddle (or sometimes a mountainpass=yes on a
highway, sometimes a valley or gorge)

> couloir (French: [ku.lwaʁ], "passage" or "corridor"), is a narrow gully with
> a steep gradient in a mountainous terrain. Tag as a gully??

Natural=gully sounds fine. I know mountain climbers talk about these
often, but there isn't a clear distinction from a gully or small
valley.

> Depression = A sunken place.

Also called sink. The low point of one of these is the opposite of a
peak - but usually they are only found in arid areas or karst, since a
lake normally forms.

We do have the approved tag natural=sinkhole for one common type of
depression, which can work for places where a stream disappears
underground as well.
https://wiki.openstreetmap.org/wiki/Tag:natural%3Dsinkhole

Most other sinks and depressions will be the site of an ephemeral
lake; eg Badwater in Death Valley, lots of intermittent desert lakes
in Australia.

> Gully = natural watercourse, especially a hillside,  It only carries water
> after rain and its sides are generally steep. Usually one of the smallest
> branches of a drainage system, and often associated with erosive action.

Natural=gully is in use, but not very common. Many could also be
mapped as an intermittent stream. If there are steep slopes
natural=cliff or natural=earth_bank can be used.
https://wiki.openstreetmap.org/wiki/Tag:natural%3Dgully

> fjard = (Swedish: fjärd, IPA: [ˈfjæːɖ]) is an inlet formed by the marine
> submergence of formerly glaciated valleys and depressions within a rocky
> glaciated terrain of low relief. Fjards are characterized by a profile that
> is shorter, shallower, and broader than the profile of a fjord.

Never heard of this before! Wikipedia says: "A fjard is a large open
space of water between groups of islands or mainland in archipelagos.
" It's related to the word "fjord". It sounds like this would usually
be a natural=strait or perhaps natural=bay?

> Fjord ? Not in the data base??? Yet fjard is.

Fjords are often tagged as natural=bay plus bay=fjord:
https://wiki.openstreetmap.org/wiki/Tag:bay%3Dfjord

> fumarole =is an opening in a planet's crust which emits steam and gases
There are 2 proposals, both used less than 20 times:
geological=volcanic_fumarole
https://wiki.openstreetmap.org/wiki/Tag:geological%3Dvolcanic_fumarole
natural=fumarole
https://wiki.openstreetmap.org/wiki/Proposed_features/fumarole

> massif = a section of a planet's crust that is demarcated by faults or
> flexures. In the movement of the crust, a massif tends to retain its
> internal structure while being displaced as a whole. The term also refers to
> a group of mountains formed by such a structure.

This was proposed but abandoned, used less than 20 times: natural=massif
I'm not sure how a non-geologist could map one of these. It sounds
like they are defined by faults and subsurface rock characteristics
that are not really visible?

> Mountain = A large natural elevation of the earth’s surface. Note peaks are
> different from mountains, see below!

Most mountains can be mapped as either a natural=peak (if the named
features is a particular peak) or a natural=ridge (if the mountain is
a linear feature with several peaks), or natural=volcano sometimes.

> mountain_ridge = Use ridge? in OSM already

Yes, natural=ridge is approved

> Oasis =the combination of a human settlement and a cultivated area (often a
> date palm grove) in a desert or semi-desert environment

Just a place=village and various types of landuse and lancover around
it, no? I think it will be obvious that it's an oasis if you see
water, trees, farmland and landuse=residential in a region that is
otherwise desert wilderness.

> Plain = tract of country the general surface of which is comparatively flat
> or slightly undulating. In extent generally not less than 2,500 hectares and
> sparsely, if at all timbered.

Probably not mappable except as a node. Many of these are large
regions without clear borders. But a small plain might be mapped as a
node, like a valley.

> floodplain Use the above plain with plain=floodplain???

A floodplain is rather different. Defining a floodplain requires
knowing the statistical risk that a certain area will be flooding in
the next 10 or 100 or 1000 years, so it's not something that we can
have in OSM.

> range A series or line of mountain or hill ridges with or without peaks, in
> which the crests are relatively narrow. Its minimum length is about 16
> kilometres

This can be mapped as a natural=ridge if it's a continuous ridge line.
There was also a proposal for natural=mountain_range but it's a little
fuzzy to define the difference between a ridge and a range. They are
both "sierra" in Spanish, for example. Old proposal:
https://wiki.openstreetmap.org/wiki/Proposed_features/Mountains - also
mentions massif

> ravine = A deep narrow steep sided valley.

I would think these could be either natural=gully or natural=valley or
natural=gorge depending on size?

> thalweg  a line connecting the lowest points of successive cross-sections
> along the course of a valley or river.

The waterway=riverbank page says that waterway=river should be mapped
along the thalweg:
https://wiki.openstreetmap.org/wiki/Tag:waterway%3Driverbank

This would also be the location I would map a natural=valley as a
linear way - only in the rare situation that there is no river or
stream in the valley, due to very dry climate or karst geology with
underground streams.


> --------------------------
> Water related
>
> Dry lake, often called a playa in the south western United States. Tag as a
> lake, intermittent=yes/ephereral=yes???

+1

> Fen = one of the main types of wetland, fens are a kind of mire. Tag as a
> wetland?

wetland=fen is approved, but much less common than wetland=bog - so I
suspect that many fens are mapped as natural=wetland + wetland=bog -
https://wiki.openstreetmap.org/wiki/Tag:wetland%3Dfen

> Sink (geography), also known as an alkali flat or sabkha, a desert basin
> with no outlet which periodically fills with water to form a temporary lake.
> Possibly tag as lake, intermittent=yes, ephemeral=yes.

+1

> tarn = A tarn (or corrie loch) is a mountain lake, pond or pool, formed in a
> cirque excavated by a glacier. Use OSM lake ???

+1 natural=water +water=lake - if you want, you could add lake=tarn as well?

> ------------------
> Peaks are not necessarily mountains or hills!!!
> The highest mountain in Australia, Mt Koscciszko is a bump in a bumpy
> landscape .. it is not a 'peak'.

A natural=peak is any summit or peak; that is, any point that is
higher than the surroundings. Wikipedia: "A summit is a point on a
surface that is higher in elevation than all points immediately
adjacent to it. The topographic terms acme, apex, peak (mountain
peak), and zenith are synonymous."

I would certainly call the high point of Mt. Koscciszko a
natural=peak, because it's the highest point on the landmass. But each
of the bumps on its slopes can also be appropriately tagged as a
natural=peak, especially if they have unique names in use by locals.

If a mountain has a name that refers to the whole range rather than a
single peak, natural=ridge often works.

But in the great majority of cases, the highest peak or summit is
associated with the name of the mountain.



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