Reference: Badlands , Encyclopedia of Geomorphology ,http://bit.ly/2PagW8f
> but this is rather specific and may not be well-known outside of North > America: 'Badlands' exist all over the world. They might have local nomenclature, but they are specific type of landform recognized by the international scientific community. > But most of those could be scree or shingle, which would be more specific ... Would it be best to describe the type of soil, like natural=clay, =silt, =earth, =pebbles, =gravel? ... Should mappers use surface=* without another top-level tag?... Should natural=bare_earth be used in general for clay and other bare soils? Badlands are continuously erosional features, so you will find all of those ( and more ) in a badlands zone, often changing over a span of a couple of meters. > Or is natural=badlands best to describe the specific feature of an arid area where the bare soil is exposed due to erosion? Yes. They are defined geologically by the process, continual erosion, and most prominently by the shape of the land: basically everything is a gully or ridge, with fairly steep slopes between them. there might be transient flat areas where sediments collect temporarily, but those are then cut again by erosion. And a few flat areas where harder bedrock is exposed. At the margins above and below the badland watershed / erosional zone are usually more continuous land forms and slopes. An arid climate is not necessarily a characteristic. They are are found in all climate zones, the amount and timing of precipitation affects the occurrence, size, and speed of growth. And they may not even be 'natural': "... Badlands are common in areas with at least seasonal drought, in semi-arid and arid areas, Mediterranean and dry-season tropical areas. However, they also occur in humid regions, for example on eroding coastal and river cliffs. Badlands may result from natural processes, but their extent may be accentuated by human activity. Some badlands may be the result of human-induced soil erosion." > ... wouldn't it be useful to add, in addition to OSM-specific tags like > natural=bare_rock, natural=shingle, natural=scree, ... a tag to reference standard land cover classification? +1 Wikipedia is not an authoritative source, and varies between excellent and poor, and a lay person would find it hard to tell the difference. > The CLC is based on 1:100.000 scale satellite imagery, so it can't be as specific as what OpenStreetMap users can tag with local knowledge and aerial imagery. The final data product is aggregated, but the original imagery is much, much better than that - the 'mapping' ( cartographic ) scale is different than the data model. . The classification system itself is probably still valid a finer resolutions - past the upper level it drills down into more specific categories like "2.4.3 Land principally occupied by agriculture, with significant areas of natural vegetation" . Corine's classification system is very coarse, like USGS NLCD it is meant for continental scale changes. There are more specific standard classification systems for finer levels of landscape details, like FAO http://www.fao.org/3/x0596e/x0596e01f.htm#p971_94150
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