[Tagging] Feature Proposal - RFC - shrubbery

Mon Feb 22 21:59:23 UTC 2021

To justify my proposed improvement of Vincent's definition I' de like to
repeat it the following 3 proposed/existing definitions:

For *natural=scrub* and *landcover=scrub* (notice the singular, because
the word scrub refers to a single area containing a group of plants):
"Is used to tag areas of uncultivated land covered with shrubs, bushes
or stunted trees.
When scrub is found where human intervention is clear to influence it's
interior growth or propagation to serve it's appearance to be more
attractive to humans or to control it's growth to not interfere with
other human activities, like landscaping, gardening, in or on cultivated
land, natural=shrubs should be used instead. If the human activity is
aimed at controlling it's propagation at it's boundaries only or to keep
it in it's indigenous natural state, f.i. by clearing invasive species,
it is to be tagged as natural=scrub. Typically the height of the
vegetation varies between approx. 0.5m and 5m (indicative, not hard
values) to distinguish it from *natural=heath* and *natural=wood*.

For *natural=shrubs* "Is a group of shrubs or bushes, characterised by
stems with mostly a woody appearance and branches appearing at or close
to the ground. In some cases the stem(s) are not woody like f.i. in most
cacti and some low growing bamboos." This tag should only be used for
vegetation, with this distinctive appearance, that shows a top foliage
not higher then 5m? and not lower then 20 cm ? Similar woody vegetation
lower then shrub should be tagged with natural=heath. Vegetation showing
a higher foliage is to be mapped separately as individual trees, tree
rows or natural=wood or landcover=trees.
Shrub is in most cases found where human intervention is obvious on the
growth or propagation of the vegetation. Examples are f.i. landscaping,
gardening, in or on cultivated land. If the human intervention is
intended just to control it's uncontrolled propagation at it's
boundaries or preserve the indigenous and/or natural character of the
vegetation in it's interior, for example by clearing invasive species,
natural=scrub should be used instead. A similar definition can be used
for *landcover=shrubs*. *Natural=shrub* or *natural=bush* is used on a
node for an individual plant in this group.
Typically the height of the vegetation varies between approx. 0.5m and
5m (indicative, not hard values) to distinguish it from *natural=heath*
and *natural=wood*.

For *natural=heath* "is used to map areas of *heath* or *heathland*: a
dwarf-shrub habitat, characterized by open, low-growing woody
vegetation, often dominated by plants of the Ericaceae (Heather). See
Heath <https://en.wikipedia.org/wiki/en:Heath> on Wikipedia. The tag
natural <https://wiki.openstreetmap.org/wiki/Key:natural>=heath can be
applied to any similar habitat worldwide. Typically this vegetation does
not grow higher then 0.5m (indicative, not hard value) to distinguish it
from *natural=scrub* and *natural=shrubs*."

@Peter:

> I agree that consumers are unlikely to look for "shrubbery", but that
> "shrubs" could be a useful value for landcover=*.
I looked at many classification systems, as you might well know many of
them have different classifications depending on the purpose they are
mapped for. I nearly all of them, who try to analyse landcover in
countries, the term scrub or scrubland is used.  However, classification
systems trying to map smaller areas like f.I. in a smaller urban context
use shrub or shrubland.  Even some renowned national mapping
classification systems just use shrub and abandoned scrub.Example:
https://www.fs.fed.us/emc/rig/documents/integrated_inventory/FS_ExistingVEG_classif_mapping_TG_05.pdf.

> FWIW, I disagree with the contention by @Vincent that a "shrubbery"
> MUST contain a path.  He cites wikipedia as his source, but IMHO
> wikipedia is not infallible.  I could envisage a garden containing a
> lawn (managed grass), with a collection of planted and managed shrubs
> beyond it, which would be called a "shrubbery".  I also see little
> point in mapping an area in OSM to say that "in this area are some
> tended plants and some paths", but not mapping the paths.
True. But we would advise to tag shrubbery due to it's controversy, by
attribution as a specific form of shrub.  Any paths should be mapped
separately as paths running through the area tagged as *natural=shrubs*
and *shrubs=shrubbery*.
> It is unfortunate that "scrub" and "shrub" differ by only one letter,
> but we manage to distinguish between a "car" and a "cat" ;-) 
Haha, very well said. But also consider that most languages have no
decent distinguished translation for "shrubbery".  Scrub is singular, as
it describes a single area or group of plants. Shrubs is plural and a
keen mapper should be informed and notice this difference.

@Martin:

> if it is not woody (specific low growing bamboo), it would be "grass",
> or not? (I am not a botanic, as you may see from this sentence).
Very well noticed.  Scientifically bamboos are grasses. However, in many
cases very distinctive from grasses, like in my region we have large
forest of just bamboos growing up to a height of 20m.  You wouldn't want
to call them grass for a non-scientific mapper do you ?  In my opinion
they deserve there own natural= tag just as maybe cacti. However, try to
limit our discussion to shrubs now.  SO bamboo and cacti, who don't
necessarily have a woody stem should be considered as grass, heath,
shrub or scrub or wood according to the height observed by the mapper.

> I would not add a height definition either, but I believe it would be
> crucial to distinguish this  new tag from "natural=scrub", and to
> specify how exactly it should be applied.
The height is not added to distinguish from natural=scrub, they are
exactly the same heights. They are to distinguish from the next lower
and higher, also mainly woody vegetation namely natural=heath and
natural=wood.

>  Could I add it to a surface where both, grass and shrubs are growing?
Of course, but you use the general consensus that the vegetation
creating the top foliage, covering most of the land, determines the main
tag.  This applies for all natural tags and vegetation in landcover
tagging. F.I. 1 acre of grassland with 2x 5m crown diameter trees is not
called natural=wood. An area of scree with two 20cm patches of grass is
not called natural=grassland.
> Can I walk over it? Step through them between the bushes, or would it
> be too dense and I should regard it as an obstacle which I would avoid
> at all costs?
We don't say anything about it, just refer to barrier=hedge.  If it has
the very particular function to obstruct free movement AND it has a
predominantly linear character, barrier=hedge should be used instead.
barrier=hedge is also used for linearly aligned shrubs or bushes that
have a boundary or border function.  However this is in the "grey"
zone.  Looking at it's primary characteristics, as the hedge is to be
considered to be mapped as a physical barrier (for movement) due to it's
controversy support of not being mapped as an area I would propose to
use natural=shrubs. The opposite is also true, we don't actively support
using natural=shrubs for ways, you should use barrier=hedge instead
because a barrier can also be intended to preserve privacy f.i. or as a
low growing hedge to achieve an aesthetic border effect.
> Is it a feature you would expect to be tagged in a garden or urban
> park, in plains, in the jungle?
Both scrub and shrubs may be used.  Depends on the human intervention of
the vegetation. Garden or urban park: will be mostly shrubs but we do
not disapprove to use scrub when it is an island of pristine scrub or
maybe purposely planted by humans to provide an untouched an free
growing natural environment as a patch or even a whole garden or urban
park.  The human intervention on the growth and propagation is the key
distinguishing factor here. Plains and in the jungle will in most cases
be natural=scrub although you might find islands of shrub within them,
based ion the same amount of human intervention.
> What about spines/thorns? What do we use for bramble?
Spines thorns are also found on trees, heath.  If you want to
specifically warn someone about their presence you can use the hazard
tagging. Bramble mostly grows up to a height above 0.5m (as the single
branches pile up). So=shrub unless it is a species that is maintained
and consistently stays below 0.5m then =heath. The height definition
becomes the distinguishing key factor. Also fro bramble you could use
the hazard to warn for the spikes or thorns.  In both case you could
aslo add shrubs=bramble or heath=bramble or use the species or taxon
tagging to be more specific.

> Is scrub the same as thicket, coppice and covert?
> brush?
Depending on the height, a thicket would be natural=scrub or natural=wood.
Coppice very clear natural=shrubs because it's lower then 5m and
requires continuous human intervention. I would add shurbs=coppice.
Covert see thicket.
Brush grows below trees so the top foliage determines the tagging of the
area will be natural=wood and/or landcover=trees.

@ Peter Elderson:

> a shrub is one plant (natural=shrub)
Correct, or natural=bush.

> natural=shrubs (or landcover=shrubs) would mean a group or an area of
> shrubs.
Correct.

> natural=scrub would be wider, maybe managed but less manicured area of
> shrubs and low stunted trees on e.g. a grassy or sandy ground. 
Forget the ground.  We say nothing about the ground except, that
natural=scrub, by it's nature and pure definition can only grow on
uncultivated land, but so does shrubs.  Mulching or weeding does not
make a land cultivated though.  Cultivated land is land on hich
vegetation is grown to produce crops or fruits for human consumption.
Less manicured is confusing, the inner part is NOT manicured at all,
except of some minor interference of removing invasive species or maybe
to avoid it's uncontrolled propagation. At the boundaries it can be
maintained, f.i. clipping cutting only at the borders to prevent
extensive overgrowth of a highway f.i., border stones or other
confinement to prevent uncontrolled spreading of shoots can all be
applied to scrub as well as shrubs.

> The old hedge area could maybe qualify as a shrubbery.
It could however if you find it convenient or significantly wide to be
mapped as an area and it has not a clearly distinctive barrier function
we would advise to use natural=shrub for areas.  It is to be mapped as a
way it will always be barrier=hedge, natural=shrubs does not support
ways as linear features. This approach also bypasses the rendering issue
in OSMcarto.

> However,  when a "left over" piece of land with no apparent primary
> use, or rather a mix of presumed uses,  is covered with vegetation,
> with no predominant type, it's just greenery. Can be scrub now,
> flowers might dominate in summer, grasses grow hip-high when the
> flowers are gone, or they plow, mow and redesign it every other year.
> Then it's landcover=greenery or natural=greenery. 
> That's what the Dutch call "gemeentegroen" (municipal greenery),
> often confused with village_green but that's an entirely different
> feature. 
I am not that familiar with the Dutch term "gemeentegroen" but if the
area is consisting of dominantly shrubs and/or bushes I would use
natural=shrubs.  It is more specific.  Additional significant trees can
be mapped as individual nodes with natural=tree. Greenery is OK but more
general, consider natural=shrubs as a means of providing more detail but
you are free how to tag it in regard to your local context. Anyway, all
of these are guidelines, not roles, you are free to tag however you want.

Greetings to all,

Bert Araali

On 22/02/2021 20:05, Peter Neale via Tagging wrote:
> Thank you, @Bert Araali,
>
> I agree that consumers are unlikely to look for "shrubbery", but that
> "shrubs" could be a useful value for landcover=*.
>
> FWIW, I disagree with the contention by @Vincent that a "shrubbery"
> MUST contain a path.  He cites wikipedia as his source, but IMHO
> wikipedia is not infallible.  I could envisage a garden containing a
> lawn (managed grass), with a collection of planted and managed shrubs
> beyond it, which would be called a "shrubbery".  I also see little
> point in mapping an area in OSM to say that "in this area are some
> tended plants and some paths", but not mapping the paths.
>
> It is unfortunate that "scrub" and "shrub" differ by only one letter,
> but we manage to distinguish between a "car" and a "cat" ;-) 
>
> Regards,
> Peter
>
>
>
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