|Status:||Proposed (under way)|
|Definition:||Key landcover to enhance description possibilities for areas|
This proposal was created in 2010 to introduce the key landcover=* to be used for describing the physical cover of an area (grass, trees etc) as distinct from landuse=* which is used to describe the human use of the area and also distinct from geographical features as described with natural=* (Note that since 2010 some values have been introduced into the natural key which do not fit into the definition of geographical feature, e.g. "natural=mud"). These concepts are orthogonal, for example both, a sports pitch and a car park, can be covered with grass or asphalt; equally one can have a landcover of grass within a park, a garden, a road verge, an aerodrome or a meadow for grazing cows, which are all different landuses.
This distinction reflects the two traditional branches of geography : Physical geography and Human geography. Clearer tagging of the form proposed will facilitate more rigorous scientific uses of OSM in the fields of biology, geography and geology. It will enable scientists to contribute their data to OSM, as well as the use of OSM as a scientific tool.
The current situation
Landuse information is already provided, mainly by landuse=*, but landuses are also covered by amenity=* (car parks, schools, universities, hospitals etc) and by leisure=* (park, recreation ground etc).
Landcover information is already available in OSM, but is spread across many keys - such as landuse, natural and surface. Some values of landuse are actually landcover, for example landuse=grass. Since 2010, the landcover key has gained some followers, and while there is no principal app (editing or rendering) supporting the tag, there is some usage.
The current tagging makes it difficult to tag some features. For example, a military area which is covered with grass can't be tagged both with landuse=military and with landuse=grass (e.g. the tag leisure=park is definitely wrong). Meanwhile, the official definitions for the tags landuse=forest and natural=wood have been "downgraded" to mean nothing different from "there are some trees here".
This proposal aims to provide a consistent structure to resolve some of the semantic inconsistencies in the tagging scheme and to ensure that it is always possible to provide both: a landuse and a landcover for every location.
As of January 2016, landcover=* had 17,912 uses according to taginfo. In September 2018 this had increased to 67,000. In March 2019 usage was 170,000 objects, of which 96,000 objects were found to be from an organized mapping effort in Paraguay (resulting in 74,000 non-related objects).
The existing landuse=* tag would be retained for human uses of land, including: Economic activities, transportation, construction, tourism, history and culture, industry. Most of the landuse=* definitions currently in use are indeed already a part of this domain, but some tags will need to be transitioned to reflect the more systematic tagging scheme. A 'landuse=highway' should be added to cover land forming part of a road (including carriageway, footways and verges). The 'landuse=grass' tag could be deprecated with landcover=grass taking its place.
The natural key could also be reviewed. Most of the values there actually describe geographic features, as distinct from landcover or landuse. but there is also some exceptions that might be better suited in landcover, for example natural=sand and natural=mud.
The landcover key with the following values:
|landcover=trees||for any area covered with trees, regardless of it being natural or not, in a forest or in a park/garden, etc.|
|landcover=grass||for any grass covered area|
|landcover=water||likely not needed, refer to natural=water, see below|
|landcover=scrub||actually used value|
|landcover=bushes||less used value, might mean the same as scrub|
|landcover=bare_rock||uncovered, bare rock, at most sparsely vegetated||bedrock
|landcover=loam||mixture of sand, silt and clay (deprecates natural=mud), without or with sparse vegetation|
|landcover=compacted_hardcore||a surface of hardcore material which has either been compacted on purpose or through use|
|landcover=ice||for areas covered the whole year with ice (see also natural=glacier for ice masses that move on their own)|
While duplicate tagging isn't a problem as such, the following tags will often not imply more meaning than the landcover tag:
- natural=mud (e.g. landcover=ground, bare_ground)
- natural=sand (same meaning as landcover=sand)
- landuse=grass (often used as a generic grass area: landcover=grass)
- surface=* Surface is mainly used for line features, e.g. to assist with routing.
The following tags are extremely established and very unlikely to change:
- natural=water (it would actually be logical to have landcover=water and natural=lake/sea/ocean... but I am not sure about the benefit of a change to a tag so extensively used. Comments?)
Areas, can and should be combined with geographical features (natural) and landuse.
Please use the discussion page.
Also see some comments here: