[Tagging] Feature Proposal - RFC - landuse bush

[Bert -Araali- Van Opstal]

My apologies for this long mail,but I kindly request to take your time
and go through the references, my personal conclusions/proposal sofar
resulting from the ongoing discussions.

I did some more research to clarify on the issue and I kindly request to
streamline this discussion. I enjoy and encourage the ongoing discussion
and respect every bodies opinion. However, we are getting nowhere and
end up with confused mappers doing their own thing, creating more
mapping and tagging variants and inconsistencies. We get a  "mess" which
is ever more difficult to solve in the long term, doesn't serve our
communities cause and data consistency.

My research summary and what so far came up in the discussion:

Ref.A - OSM wiki on natural=scrub (: "The tag natural
<https://wiki.openstreetmap.org/wiki/Key:natural>=scrub is used to tag
areas of uncultivated land covered with shrubs, bushes or stunted
trees."  and important the definition on
key:natural = "wide variety of physical geography, geological
<https://wiki.openstreetmap.org/wiki/Geological> and landcover
<https://wiki.openstreetmap.org/wiki/Landcover> features, including ones
that have been modified or created by humans
<https://wiki.openstreetmap.org/wiki/Counterintuitive_key_names>.
It is also referenced in the Feature:vegetation wiki page together with
natural=heath and barrier=hedge which also appeared in the discussion as
possible solutions and strongly related:
scrub on Feature:vegetation = "Uncultivated area with shrubs, bushes or
stunted trees - taller than heath."
heath on Feature:vegetation = "Uncultivated area with dwarf shrubs and
bushes - shorter than scrub."
hedge on Feature:vegetation = "Shrubs arranged in a dense line to form
an impassable hedge" and
hedge on Bariier:hedge = "barrier
<https://wiki.openstreetmap.org/wiki/Key:barrier>=hedge is used to
identify a line of closely spaced shrubs and tree species, which form a
barrier or mark the boundary of an area. Hedges may be actively managed,
but this is not always the case." and important
Key:barrier = "A *barrier* is a physical structure which blocks or
impedes movement." and for hedge on
key:barrier:hedge = "Is a line of closely spaced shrubs and bushes,
planted and trained in such a way as to form a barrier or to mark the
boundary of an area. "

Ref.B - WIkipedia: "*Shrubland*, *scrubland*, *scrub*, *brush*, or
*bush* is a plant community
<https://en.wikipedia.org/wiki/Plant_community> characterized by
vegetation <https://en.wikipedia.org/wiki/Vegetation> dominated
<https://en.wikipedia.org/wiki/Dominance_(ecology)> by shrubs
<https://en.wikipedia.org/wiki/Shrub>, often also including grasses
<https://en.wikipedia.org/wiki/Grass>, herbs
<https://en.wikipedia.org/wiki/Herbaceous_plant>, and geophytes
<https://en.wikipedia.org/wiki/Geophyte>. Shrubland may either occur
naturally or be the result of human activity."

Ref.C - from freenecyclodeia:scrub·land:
An area of land that is uncultivated and covered with sparse stunted vegetation."

Next let's summarise where, of course my analysis and opinion, we are at
this time on the discussion requested for the proposal (landuse
<https://wiki.openstreetmap.org/wiki/Key:landuse>=shrubs to define an
area of bushes on cultivated land and in the built environment, often
used for decorative purposes or to fill space and where barrier
<https://wiki.openstreetmap.org/wiki/Key:barrier>=hedge
<https://wiki.openstreetmap.org/wiki/Tag:barrier%3Dhedge> does not apply.
To make it simple lets split it:
Question 1 - Do we need a newlanduse=shrubs or bush. To my analysis we
have consensus on this: NO.
Shrubs are covered by natural=scrub as all references, including the
existing OSM wiki page clearly states that scrub includes bushes, shrubs
etc... . Landuse is a wrong key anyhow since we want to describe
vegetation, not the use of the land since the examples given are
vegetation located in an area which can be clearly identified with
existing landuse, leisure or amenity keys. So natural would be the most
suitable key. However in natural we also have scrub which covers this
type of vegetation. Landcover or landform as alternative (see discussion
page). The answer is no again since landcover is less commonly used then
natural to describe vegetation, landform is a key resulting from 1
import and it can be represented by existing, mostly natural
tags.Further on, it is not recommended to overlap different landuse
areas.  Overlapping a landuse with a natural area is perfectly OK and
supported by most renderers and data consumers.

Question 2 - As the answer on Question 1 is no, can we use
natural=scrub, since scrub refers to this type of vegetation but on
uncultivated land.  The vegetation that we want to tag is on cultivated
land, or in built up areas. To my opinion yes but still under
discussion.  It depends on the interpretation of what is "cultivated land".
Notice the difference here that there is a difference in "cultivated
land", as it refers to the land where the vegetation is growing, not to
the "cultivation" of the vegetation as such! I and others didn't notice
that in the first discussions. Scrub is generally defined as can be seen
in the references as growing on uncultivated land.  The vegetation
itself, whether it is scrub or a hedge, can be maintained or not.  When
it is maintained does that mean that the vegetation is cultivated, to my
interpretation yes, a cultivated plant is by definition maintained.
Now what is the general definition of cultivated land:
(from freedictionary): "arable land that is worked by plowing and sowing
and raising crops, cultivated land that is not seeded for one or more
growing seasons is called a fallow (but is still cultivated land)"
(from wikipedia, cultivated land = arable land): "

*Arable land* (from the Latin
<https://en.wikipedia.org/wiki/Latin_language>: /arabilis
<https://en.wiktionary.org/wiki/arabilis#Latin>/, "able to be plowed
<https://en.wikipedia.org/wiki/Plow>") is any land capable of being
ploughed <https://en.wikipedia.org/wiki/Plough> and used to grow crops
<https://en.wikipedia.org/wiki/Crop>.^[1]
<https://en.wikipedia.org/wiki/Arable_land#cite_note-oed-1>
Alternatively, for the purposes of agricultural
<https://en.wikipedia.org/wiki/Agriculture> statistics,^[2]
<https://en.wikipedia.org/wiki/Arable_land#cite_note-2> the term often
has a more precise definition:

    "Arable land is the land under temporary agricultural crops
    (multiple-cropped areas are counted only once), temporary meadows
    <https://en.wikipedia.org/wiki/Meadow> for mowing or pasture
    <https://en.wikipedia.org/wiki/Pasture>, land under market
    <https://en.wikipedia.org/wiki/Market_garden> and kitchen gardens
    <https://en.wikipedia.org/wiki/Kitchen_garden> and land temporarily
    fallow <https://en.wikipedia.org/wiki/Fallow> (less than five
    years). The abandoned land resulting from shifting cultivation
    <https://en.wikipedia.org/wiki/Shifting_cultivation> is not included
    in this category. Data for 'Arable land' are not meant to indicate
    the amount of land that is potentially cultivable."^[3]
    <https://en.wikipedia.org/wiki/Arable_land#cite_note-3>

A more concise definition appearing in the Eurostat glossary similarly
refers to actual rather than potential uses: "land worked (ploughed or
tilled) regularly, generally under a system of crop rotation
<https://en.wikipedia.org/wiki/Crop_rotation>".

Now the proposal refers to bushes or shrubs that are grown on cultivated
land or in built up areas.  The only cultivated land where we find
bushes or shrubs to produce crops (or fruits) are orchards and (parts
of) gardens, allotments, and maybe some plant nurseries. intended for
producing crops. All other land is per definition NOT cultivated land.
Within these land uses, as well as in farmland, one in general does not
map the individual crop or fruit producing bushes, we map and tag them
with the corresponding landuse tag.
However, parts of the land-uses can be reserved or left uncultivated. It
is appropriately to draw areas on the land uses and tag them as scrub or
heath, as the land where this type of vegetation grows is PER DEFINITION
not cultivated since you have to remove the vegetation to be able to
cultivate that land. Same as we can find trees that does not produce
crops or fruits on cultivated land, purely ornamental, decorative or
whatever other use. Best practice would be to use multi polygons with
inner parts but we have to decide if overlapping is acceptable since it
is clear by using the scub that the land underneath is not cultivated.
Anyway, this will again open the discussion if we can overlap different
landuses like residential with orchard etc..., yet for practical reasons
in my opinion should be discussed separately.
Does this mean it can be used for the examples given in the proposal:
yes. The landuse defines the use The use is further detailed by the fact
that shrub or bushes because the natural=scrub are never used for shurbs
or bushes producing crops or fruits intended for regular harvesting.
Their primarily purpose within (not on, clearly within) a stretch of
cultivated land is defined by the landuse tag. Does this need a managed
tag ? Is optional, the manage tag does not define it's use. Does this
need another key:vaue to define its purpose as decorative / habitat for
fauna / bird nesting etc..., we need a proposal for that. Already
proposed is "Usage", seems to me not appropriate in regard to it's use
with pipelines, waterways etc.... Another candidate is "denotation" as
with trees which seems to me a very suitable candidate.
Can it be used within a built up area, of course, no problem there as
the built up areas are defined with landuse tags.

Question 3 - Barrier=hedge does not apply.
Refer to the references at the top. Hedges have a clear specific use
case: to create a barrier, boundary or border (decorative hedge).  The
have a typical linear character. Now where it says that a cultivated
bush or shrub is a hedge, in the contrary, a hedge can be not cultivated
and it is specifically described and defined as such. It even covers
hedges that are not managed or maintained. You can argue, but we can
define hedges as areas.  Yes, true (regardless if that is rendered
correctly, should be a separate discussion), same as we can define walls
as areas yet they are also rendered only as lines, even with a area=yes,
but again that's a different issue. To my opinion there is two main
requirements to classify a scrub, bush, shrub or groups of them as
hedge: 1) linear character, even if mapped as an area the area needs to
be predominately linear 2) it has the primary use as a barrier, border
or boundary.
To answer the problem trying to be solved in the proposal: 1) in some
given examples (nr. 3) could be interpreted as linear, All others no,
not linear at all. 2) the primary purpose is decorative, the barrier
effect in some cases (like on the parking) is by kerbs or other type of
barriers, no border or boundary use. So to my opinion in regard to the
proposal but still open for discussion: barrier=hedge does not apply in
these cases.

SUMMARY:

Question 1: consensus on no support creating another top level
key:value. landuse:shrub / landuse:bush. Landcover and landform surely
not supported.

Question 2: natural=scrub should be used, mapped as an area on or within
an area with a defined landuse. managed=* is optional, denotation as
with trees to further define it's significance.. Actions: extend the
related wiki pages with description of what is cultivated and
uncultivated LAND and how to map and tag + what is to be used to map and
tag cultivated and/or managed VEGETATION (regardless if it is located on
cultivated or uncultivated land).

Question 3: barrier=hedge should not be used in these cases.  It should
be used when the vegetation is predominately linear AND has either a
primary purpose or use as barrier, or boundary or border. Hedges covers
both managed / maintained as unmaintained / not managed. ("cultivated"
has never been used as a term with hedges as far as I can recall).

Greetings and keep discussing !
Bert Araali

On 13/02/2021 16:30, Volker Schmidt wrote:
> This looks again a confusion of scrub and shrub
>
> On Sat, 13 Feb 2021, 12:01 Peter Neale via Tagging,
> <tagging at openstreetmap.org <mailto:tagging at openstreetmap.org>> wrote:
>
>     IMHO Scrub that has been managed is not scrub any more.
>
>     The Wiki says, "The tag natural
>     <https://wiki.openstreetmap.org/wiki/Key:natural>=scrub is used to
>     tag areas of uncultivated land covered with shrubs, bushes or
>     stunted trees."
>
>     ..and see also, https://www.thefreedictionary.com/scrubland, which
>     says, 
>
>     "
>
>
>         scrub·land
>
>       (skrŭb′lănd′)
>     /n./
>     An area of land that is uncultivated and covered with sparse stunted vegetation."
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20210214/cd8ffe55/attachment-0001.htm>