[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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