Proposed features/landcover=clearing

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"clearing"
Status: Proposed (under way)
Proposed by: Warin61
Tagging: landcover=clearing
Applies to: node, area, relation
Definition: An area where surrounding larger vegetation is not present.
Rendered as: no rendering
Drafted on: 2018-08-04
RFC start: 2018-08-06
Example, from grass clearing to trees.

Usage

landuse=clearing

natural=clearing

wood=clearing

landcover=clearing

Proposal

There are a number of undocumented instances of the value 'clearing' in the data base. This proposal seeks to combine them, document them and suggest better ways mapping of them.

Most of these are HOT entries using the tag landuse=clearing. Others are natural=clearing, wood=clearing and landcover=clearing.

Definition

An area where surrounding larger vegetation, such as trees, are not present. This provides more light than the surrounding area. It may have lower vegetation growing, or it may be an outcrop of rock.

Rationale

Defines use of already existing value and suggest better ways of mapping these features. It is meant to encourage better mapping and suggest that this tag is a last resort.

Key

The key landcover is use as the 'best fit' as it marks the lack of a surrounding land cover, so it is directly related to a land cover.

The area could all ready have a land use - part of a forestry area for example. The area could have been made by man or nature so neither of the keys natural or man_made would suit all situations.

How to map

The section on 'how to map' gives 4 options of how to map a clearing; map what is there, map what is surrounding, map both what is there and surrounding or map with landcover=clearing.

Asking a mapper not to map this feature is not a good idea, mappers should be encouraged to map not discouraged. If a mapper has found this tag page then it is best to document better ways to tag the feature with this tag being the lest desirable result that maps the information rather than not mapping the information.

The listed order is a compromise. The better mapping ones come before landcover=clearing to discourage it use. The simplest option first - map what is there - as that is the easiest option. If they cannot determine what is there then the next option - map the surrounds. Then the combination of the first two. Then finally the last option and least desirable. Hopefully this causes some though on what they are mapping, rather than just using the tag.

How to map

Best to map the clearing as a closed way to form an area. Worst case would be to map it as a node, but this should be avoided by using satellite imagery. If the area shares ways with other things then you might use a multipolygon relation. What tagging to use is detailed below.

Map what is there in the clearing

Map what is there, be it a land cover such as shrubs or a land use such as a camp site. These can be rendered as they have information. See Landcover and Landuse.

Map what is surrounding

Map the feature that surround the area as a multipolygon relation with this area as a member with the role inner. This normally results in a blank area on the map surrounded by the tagged feature. In this case the way should not be tagged with landcover=clearing as that information is inherent tagging of the way and the relation.

Note: Some tree areas are very large and have complex boundaries. If you lack time or skill then simply map a straight sided rectangle as the outer way - mappers will recognise these as not being the true extent of a tree area and may come along later to extend it. You may have time to map some true extent of it, but then leave a section or two as straight lines with a similar message.

Map both of the above

This gives both pieces of information - the surroundings and the area itself, resulting in a better map. In this instance the inner way would have tags to say what it is while still be included with the role inner in the surrounding relation.

Map as landcover=clearing

This is the least informative. It will not render. Other mappers may be able to use it if they can resolve either what is there or what is surrounding and then map it as above.

Use fixme tag

Standard method to mark unfinished work is to use fixme=*. If someone is unable or unwilling to map what surrounds clearing then fixme may be used to mark that mapping is interrupted and left in unfinished state.

Applies to

Areas. They may be entered as a node but this is discouraged. Usually when included in a relation the tag performs no further function and can be removed.

Rendering

None. A blank piece of the map. The befit of having the information is that someone may come along later and use it.


Features/Pages affected

None. I don't think the page should be "advertised" but be presented in a search for 'clearing'.

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