[Imports] Slovenia landcover import RABA-KGZ review
Christoph Hormann
chris_hormann at gmx.de
Sun Jul 12 16:36:11 UTC 2015
On Sunday 12 July 2015, colored stone wrote:
> Please find clarifications/explanations on the Slovene agricultural
> land use (shortly RABA-KGZ) to OSM tag translations. For the
> clarifications we have mainly used the “methodological paper on
> agricultural land use” or “the interpretation rules” available at
> http://rkg.gov.si/GERK/documents/RABA_IntKljuc_20131009.pdf.
> [...]
Thanks for the additional information. I won't argue the points based
on the methodological paper in detail since i can not read it in the
original language and i am not sufficiently familiar with the data to
judge how well the actual data complies with the specifications.
A few general points though:
- use of landcover tags, in particular things like natural=scrub and
natural=heath in OSM is frequently quite inprecise. This is not a good
reason to be less strict with tagging in an import.
- the OSM landcover tagging unlike the classification scheme of your
source data is not a closed system. Not every area on earth matches
one of the OSM tags.
- individual positive examples do not mean much - no one questions that
each of the source data classes also contains areas that match the
planned OSM tags. The question is how much of the data does *not*
match the planned tagging.
Therefore here a few examples from the already imported data of what
does not match your planned tagging:
natural=heath:
http://www.openstreetmap.org/way/353487056
http://www.openstreetmap.org/way/353231651
http://www.openstreetmap.org/relation/5271375
As far as i can see most of these are grassland (or other herbaceous
vegetation like ferns as well as Blackberries, other Rosaceae and
similar plants) with a varying amount of larger scrubs and mostly
smaller trees. In many cases this is land that is in the process of
being reclaimed by trees - either previously cut forest areas or former
farmland no more used. natural=heath specifically means dwarf scrub
vegetation (that is species that naturally do not grow tall, not young
trees). In Slovenia's climate this is rare outside high mountain
areas.
Interestingly most areas that would qualify as natural=heath are
probably included in class 5000.
natural=moor (to be natural=fell):
http://www.openstreetmap.org/way/353333307
http://www.openstreetmap.org/relation/5274011
as well as all other areas with this tag except for the Alps - none of
this is close to the alpine tree line so natural=fell does not match.
Use in the Alps is questionable as well but since natural=fell is a
fairly vague tag you can't really say it is wrong.
natural=bare_rock:
http://www.openstreetmap.org/way/351883914
that is a great example for natural=scree - and here it is specifically
excluding the rock area above
http://www.openstreetmap.org/relation/5252002
mixture of bare_rock, scree and sparsely vegetated areas
http://www.openstreetmap.org/way/353153325
that would be natural=shingle
--
Christoph Hormann
http://www.imagico.de/
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