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Description broader than current tag use

I'd advise caution here - from a quick look current use of glacier:type=rock so far seems to be fairly narrowly following the common understanding in sciences on what a rock glacier is (namely a permafrost phenomenon and not - like a normal glacier - a body of moving ice that has formed from snow). The page text extends that to also include any glacier with a significant fraction of solid material - which would be an unfortunate blurring of tagging semantics.

Note in addition to glaciers, on-glacier moraines (solid material on/within a glacier and moving with it), off-glacier moraines (glacier transported till deposits off a glacier) and rock glaciers there is also ice cored moraines - which are fairly widespread and extensive in polar regions.

--Imagico (talk) 21:15, 25 July 2023 (UTC)

@Imagico: if you are familiar with current tag use: feel free to edit that page to fix it! I based this description on content (though now I see "not originating from snow", I will add it here - is it resolving it?) Mateusz Konieczny (talk) 11:21, 26 July 2023 (UTC)
Yes, i think that is better. --Imagico (talk) 14:27, 26 July 2023 (UTC)
Regarding feel free to edit that page to fix it! - I know, but as you can see it did not take long for people trying to to document how they would like mappers to map rather than documenting how they actually map to take over the page. So why bother? Sigh. --Imagico (talk) 17:03, 28 July 2023 (UTC)
I think the discussion about using natural=scree is based on documenting how people actually map this type of feature. Was there something different you wanted to see on this page? --B1tw153 (talk) 18:06, 28 July 2023 (UTC)
There is so far no substantial use of natural=scree for explicit mapping of rock glaciers to be found in the database. Use of natural=glacier for this purpose, however, both with (in particular South America) and without glacier:type=rock (like in Afghanistan), goes into the hundreds. --Imagico (talk) 19:18, 28 July 2023 (UTC)
There seem to be differing opinions about whether natural=scree has been used to map rock glaciers. Perhaps you'd like to join the discussion on the OSM Community Forum to share your perspective? --B1tw153 (talk) 19:49, 28 July 2023 (UTC)
As already indicated i have no interest in participating in a discussion what is and what is not the subjectively desirable tagging or the inevitably ensuing wiki-fiddling coming out of that. I am only interested in how the tags are actually used by mappers. This is not a matter of opinion, this is a matter of what is objectively in the database. --Imagico (talk) 20:18, 28 July 2023 (UTC)
People in that discussion asserted (maybe incorrectly) some things about current use, more info, especially from people knowledgeable on this topic, is welcome Mateusz Konieczny (talk) 20:51, 28 July 2023 (UTC)
Yes, i understand that some people - like you - are indeed interested in this. As demonstrated, however, there is unfortunately not a consensus to separate this (gathering knowledge on the de facto meaning of tags) from the much more popular discussion of how mappers should map things and the attempts to engineer the wiki to nudge mappers to do so. Old problem, discussed plenty of times already. --Imagico (talk) 21:36, 28 July 2023 (UTC)
I wrote a blog post showing that rock_glaciers -- in the Eastern Alps at least -- rarely get explicitly mapped - but rather the scree under which they hide -- which is said to be constituent for their survival, not just arbitrary. Also, 1923 of 2219 active rock glaciers in the reduced sample set belong to the "talus derived (ice-cemented)" kind. --Hungerburg (talk) 17:13, 29 July 2023 (UTC)
Confirming my observation that natural=scree is practically not used substantially for explicit mapping of rock glaciers so far. And if undifferentiated mapping of non-vegetated areas with natural=scree in Austria sometimes includes either rock glaciers or debris covered normal snow derived glaciers or moraines (i.e. glacial till rather than scree) is not really that relevant when discussing use of glacier:type=rock. Bottom line: As already indicated most explicit mapping of rock glaciers so far exists outside of Europe (which is quite natural since most rock glaciers on the planet are also outside of Europe). --Imagico (talk) 18:52, 29 July 2023 (UTC)
Looking at***/glacier%3Atype/rock I'd say, most of the mappings are from few concerted efforts, most prominent end 2016, where more than half of stock got mapped in short time. Looking at the overpass linked from taginfo and browsing a bit made me craft - so out of 400 rock glaciers mapped in Chile/The Andes, 308 are of a single user and still at version 1. Considering that there are shy of 440 mappings world wide, I'd say, mapping rock glaciers is a spleen of two people at most.
The three rock glaciers in Austria that are explicitly mapped - ie. they have the glacier:type=rock tag, are true rock glaciers according to literature. That fact though has only been added to areas, that were already tagged natural=scree, perhaps because in Austria lay persons map? All I can say, from what I learned from reading up on subject, scree is less wrong than glacier, at least in the Eastern Alps. --Hungerburg (talk) 21:40, 29 July 2023 (UTC)
Again - i am not interested in discussing what is the subjectively most desirable (or most 'correct') way to map and tag rock glaciers. I am looking at how they are actually mapped. Glacier mapping in OSM in general is something only relatively few mappers are actively working on so it is fully expected that in a certain region glaciers are mostly mapped by a single mapper. In South America this is in particular jptolosa, in Afghanistan rock glaciers have been mostly mapped by Ortsangabe (who is not active any more). Both of these are genuine grassroots mapping activities rather than organized mapping. In case of jptolosa with local knowledge, in Afghanistan probably armchair mapping. --Imagico (talk) 23:22, 29 July 2023 (UTC)
The glacier mappings in Afghanistan are no more specific than the scree mappings in Austria. The genuine mappings in Chile may actually be a political statement: Because rock glaciers are not glaciers, they did not receive the legal protection against destruction by nearby exploitation deemed needed for them as well. A very honorable goal to involve openstreetmap there. I did a vote with my feet today and doubled the geological=rock_glacier mappings, there are not so many. But the feature deserves mapping. --Hungerburg (talk) 23:13, 30 July 2023 (UTC)

Mostly mapped as scree

The fine article is wrong on this, glacier:type=rock is almost exclusively mapped on natural=glacier. Unlike with the geological=rock_glacier tag, where the combination with natural=scree is more common. Further, rock_glaciers are in no way limited to arid regions. E.g. Ötztal has lots of them, it is one of the areas with least precipitation, but in no way arid. Geologists see the cause of abundance also in bedrock type.

Glaciers are here (Austria) meticulously mapped. I rather not confront the person in charge. The geological=rock_glacier tag is the better fit for mapping something that is not a glacier. But such deliberations better outside of documentation?

PS: A bit of background, why Chile is such a hotspot in rock_glacier mapping - - Curiously, they give a count of 4-5000 for all of Chile, while Tyrol, a tiny province in the Alps, counts more the 3000 - an artefact in study budget?

In case you are interested in global distribution of rock glaciers - provides a meta-analysis of the global distribution of surveys of rock glaciers. Note
  • this is a meta-analysis of research, i.e. it documents institutional scientific research of the geography and its spatial distribution and not the geography itself.
  • it includes both actual rock glaciers as well as ground moraines of former rock glaciers (termed 'relict' in the paper).
  • for several RGI regions (Including South Asia West, i.e. Afghanistan) there is no data.
--Imagico (talk) 09:36, 31 July 2023 (UTC)