I created Tag:surface=marble - OpenStreetMap Wiki
Note that for some I have not found images of specifically marble.
If someone would have good illustration, feel free to improve the page.
I created Tag:surface=marble - OpenStreetMap Wiki
Note that for some I have not found images of specifically marble.
If someone would have good illustration, feel free to improve the page.
I just hope, this “placeholder” methodology used in documentation will not spread to OSM-tagging, so people consciously tag something wrongly, just because they did not know the right tag or no right tag exists.
In plain English, “material” would tend to refer to something manufactured, like glass or plastic or brick, while “substance” would tend to refer to something more raw, like limestone or wet cement. But material
and substance
already have more specialized meanings in OSM anyways.
I suspect these tags would still creep in because mappers in some cases would be more familiar with the kind of rock than with the way it’s laid. For example, the floor of a highway=corridor
may be surfaced in slabs of polished marble. A mapper might regard that as a distinct surface because it’s so slippery. But if a subkey is more correct, the mapper may not discover it on their own without a helpful editor field.
@Minh_Nguyen You are probably the right mind to have answers for a broader subject than creating wiki pages mostly just to deprecate tags: This topic here reminds me of another one I took part of the discussion. I had the idea, to make possible some kind of autodiscovery for consumers of data by chaining in key/value pairs.
I guess, that has inspired me to tag surface=rock; rock=granite
for the scramble linked above. When a consumer reads key=value, it can look, if there is a key with the same name as the value, and use it to learn further details. Is that comprehensible?
When there is a path with surface=rock; material=granite
, how to know, that the material
applies to the surface? It might instead apply to the handrail/whatever other attributes there are?
Yes, a human who looks at the raw tags and sees this combination would know exactly what you mean. I think editing/rendering/routing software would be unlikely to do this kind of traversal automatically for any arbitrary value. For one thing, it could lead to some pretty unexpected results in other ambiguous cases:
building=school
amenity=school
school=secondary
(Built as a secondary school or now functioning as one?)building:material=rock
wall:material=rock
rock=granite
(Just one, or both?)We normally cope with these conflicts by documenting when iterative refinement is expected, but not by expecting it to occur universally. I guess this is similar to the challenge with using unrelated keys like surface
and material
together. The most predictable version of iterative refinement relies on subkeys, like surface=granite
surface:fragment_size=*
etc. (I’m making this up.)
Anyways, my point is that surface=granite
most likely refers to different things depending on the kind of feature. A granite-surfaced highway=corridor
is very likely to be surface=paving_stones
(which luckily comes with several subkeys), but the common term for that would be “granite surface plates” or just “granite surfacing”. Since granite is such a durable material, the slabs can get as large as concrete plates (concrete:plates
), but the tagging is so different that users may not know about these options.
Like others here, I’m not very concerned about determining the mineral composition of a crushed rock surface.
I think that touches on something, that concerns OSM tagging a lot: Some tags are introduced by people that care about a certain aspect, from a particular position, and later get used by people, that do not care about that aspect, having no connection to the POV of the tag creators.
Some might wonder, why Yosemite granite looks so much different than Lüsener Fernerkogel granite? (Fernerkogel is surface=rock;rock=gneiss;gneiss=granite
; while Yosemite has surface=rock;rock=granite
)
In the end, its all gravel? The challenge to replace paved/unpaved with something more specific a lost endeavour?
PS: How about surface=paved;paved=rock;rock=granite
vs. surface=unpaved;unpaved=rock;rock=granite
?
I would not go so far - even if pebblestone/gravel differentiation that someone attempted failed there is still reliable distinction (I hope) between sand
and compacted
Well taken, but surface=rock
says nothing about whether it is paved or unpaved rock. Of course, there are the keys tracktype|smoothness but how reliable is that?
How can raw natural rock be unpaved? Or paved for that matter? Why it would even matter?
(unless it is joke, then sorry for not getting it)
raw natural rock is “unpaved” I think, because it is not paved (nobody has paved it).
Let me try to find out why the confusion: It might be on my side!
surface=rock; material=granite is always natural/unpaved
surface=*stone; material=granite is always manufactured/paved
So, if it is paved, rock turns into stone. Sorry for the noise!
PS: Still words like
Natural rock, with nearly no processing used to pave a mountainous path. [Tag:surface=rock - OpenStreetMap Wiki]
do not help against confusions like mine.
ops
I guess one more reason to get surface=bare_rock
and surface=unhewn_stone
I have some stairs with blocks of solid granite. What would you put in for surface=*
- rock?
What kind of granite? Can you upload or link a photo?
Machined into flat pieces of stone? surface=paving_stones
Roughly cut? surface=sett
Uncut pieces of rock? surface=unhewn_cobblestone
Natural rock, maybe with some minimal cutting/shaping? surface=rock
This is what it looks like. No idea what type of granite that is,
I would use paving_stones
(and treat them as large rectangular paving stones made of a natural stone)
In my mind, paving_stones
requires multiple blocks arranged in some kind of pattern. If the entire surface is made from a single piece, that value doesn’t fit.
Think to have come across something that was called concrete slabs or plates, so went to search. Well openstreetmap+slabs and one of the top results in bing was Tag:surface=paving_stones - OpenStreetMap Wiki although ‘slabs’ is not mentioned once in that wiki page.
With paving_‘stones’ I think (dare I) of a format that can be easily handled by one so we certainly could do with a paving_slabs or paving_plates to express that dimension as seen above of the polished stone steps.
Not an expert, but I would say slabs is just another word for paving stones (though often made from concrete).
These are steps I would tag as paving_stones
:
The ones Nadjita showed are just surface=stone
to me. Not available on StreetComplete so I don’t answer the quest. paving_stones
feels wrong
I also wonder, why we have material=*
and paving_stone:material=*
. Why should I use something like paving_stone:material=concrete
over material=concrete
?
In theory, these steps don’t have a separate surface, as they are just a big chunk if granite, so material=granite
would be correct. But after looking at this more closer, it seems that material and surface have a lot of overlapping which makes it confusing. Actually, the surface should better describe the structure of the surface than the material, unless the material of the surface differs from the main material. So something like surface=flat
for my case, paired with material=granite
? I find this all very confusing.