Proposal:Taxonomic rank

Taxonomic rank
Proposal status:	Canceled (inactive)
Proposed by:	SebasOSM
Tagging:	taxon:rank=*
Applies to:
Definition:	A dedicated key to define taxonomic ranks.
Statistics:
Draft started:	2025-10-24
RFC start:	2025-10-25

This proposal has been canceled in favour of an ongoing discussion that is already leading to a different proposal.

Proposal

A Taxonomic rank indicates an organism’s hierarchical level. Lower ranks are more specific than higher ranks. Ranks are currently often tagged with rank-specific keys (e.g., species=*, genus=*) or with taxon-subkeys like taxon:cultivar=*. An alternative is to use only the taxon=*, but without a rank-specific key it is unclear which rank the taxon=* value represents — which is precisely the original intent of the taxon=* key.

For mappers who do know the rank, I propose a new key: taxon:rank=*. This key records the taxonomic rank using a fixed pattern. That makes taxon=* more usable because you no longer need to add rank-specific keys to indicate which rank is stored in taxon=*.

The following is proposed:

• Introduction of a two-key principle — taxon=* and taxon:rank=* — to record taxa and their corresponding rank so mappers don’t have to add extra rank-specific tags.
• Bundling of extra metadata keys (such as Wikidata and common name) under the same taxon=* key.
• Keep supporting rank-specific keys.
• Retention of taxon=*'s original loose interpretation, with the option to verify the taxonomic rank via taxon:rank=*.

Rationale

The two-key principle

Taxonomic ranks are currently spread across different keys. Basic ranks are usually tagged with genus=* and species=*, with the mapper typically tagging the most specific rank (species > genus).

Tagging becomes more complicated for infraspecific names (e.g., subspecies) and for cultivated plants. For example, Fraxinus angustifolia subsp. oxycarpa 'Raywood' is commonly tagged as:

• taxon=Fraxinus angustifolia subsp. oxycarpa 'Raywood'
• species=Fraxinus angustifolia
• taxon:subspecies=oxycarpa
• taxon:cultivar=Raywood

Because taxon=* does not state the taxonomic rank, it is unusable from a data perspective. To express the taxonomic rank we tag species=*, taxon:subspecies=* and taxon:cultivar=* separately. Yet the isolated values for subspecies and cultivar are meaningless without the context of taxon=*, so why tag them separately? It’s redundant because the information is already in taxon=*; the problem is that it’s unclear to a script or person how to parse it. taxon:rank=* fills that role by indicating the pattern of the taxon=* value. Let's apply this to the example above:

• taxon=Fraxinus angustifolia subsp. oxycarpa 'Raywood'
• taxon:rank=cultivated_subspecies

Here taxon:rank=cultivated_subspecies implies the pattern <genus> <species> subsp. <subspecies> '<cultivar>', so you don’t need to tag subspecies or cultivar as separate keys.

Extra metadata tags

Extra metadata such as Wikidata and common name are usually tagged on rank-specific keys (e.g., species:wikidata=*, genus:en=*). This metadata can instead be bundled under the taxon=* key; this is already done in part. Combined with taxon:rank=* it becomes clear which taxonomic rank the metadata refers to. For example, taxon:wikidata=* together with taxon:rank=* indicates the Wikidata Q-item for the specified taxonomic rank.

If you need metadata for a different rank — for instance if a subspecies lacks a common name but the species has one — rank-specific variants can be used, e.g. taxon:en:<taxon_rank>=*. This keeps Wikidata and common-name tags bundled under the same taxon namespace rather than spread over many rank-specific keys.

The taxon:rank=* key is optional and does not replace existing keys

This proposal aims to make taxon=* more usable and to bundle Wikidata and common names under a consistent key. taxon=* without taxon:rank=* remains a loose interpretation. Rank-specific keys remain valid and usable.

Tagging

Taxonomic Rank pattern	taxon_rank	Example	Proposed tagging	Currently tagged as
<genus>	genus	Fraxinus	taxon=* taxon:rank=genus	genus=* or taxon:genus=*
<genus> <species>	species	Fraxinus angustifolia	taxon=* taxon:rank=species	species=* or taxon:species=*
<genus> <species> '<cultivar>'	cultivated_species	Fraxinus angustifolia 'Flame'	taxon=* taxon:rank=cultivated_species	taxon=* species=* or taxon:species=* taxon:cultivar=*
<genus> <species> subsp. <subspecies>	subspecies	Fraxinus angustifolia subsp. pannonica	taxon=* taxon:rank=subspecies	taxon=* species=* or taxon:species=* taxon:subspecies=*
<genus> <species> subsp. <subspecies> '<cultivar>'	cultivated_subspecies	Fraxinus angustifolia subsp. oxycarpa 'Raywood'	taxon=* taxon:rank=cultivated_subspecies	taxon=* species=* or taxon:species=* taxon:subspecies=* taxon:cultivar=*
<genus> <species> var. <variety>	variety	Fraxinus angustifolia var. pilosa	taxon=* taxon:rank=variety	taxon=* species=* or taxon:species=* taxon:variety=*
<genus> <species> f. <variety>	form	Fraxinus angustifolia f. obtusiuscula	taxon=* taxon:rank=form	taxon=* species=* or taxon:species=* taxon:form=*

Note: Species is already a binomial name (consisting of two parts), but for clarity genus and species are separated here.

Examples

Tagging
Example #1 natural=tree leaf_cycle=deciduous leaf_type=broadleaved taxon=Prunus × yedoensis taxon:rank=species taxon:wikidata=Q163078 taxon:en=Tokyo cherry
Example #2 natural=shrubbery taxon=Calycanthus × raulstonii 'Aphrodite' taxon:rank=cultivated_species taxon:wikidata:species=Q508408601 taxon:en:genus=Sweetshrub2 1 There is no Wikidata for this cultivated species, so instead we use the Wikidata of the species. 2 There is no vernacular name for this cultivated species or species, so instead we use the vernecular name of the genus.
Example #3 natural=tree leaf_cycle=evergreen leaf_type=needleleaved taxon=Pinus nigra subsp. nigra taxon:rank=subspecies taxon:wikidata=Q4730748 taxon:en=Austrian pine

Rendering

This key does not require additional rendering.

Features/Pages affected

• Tag:natural=tree
• Tag:natural=shrubbery
• Tag:natural=shrub
• Tag:natural=wood
• Tag:natural=flowers
• Tag:natural=grassland
• Tag:natural=plant
• Tag:landcover=grass
• Key:genus
• Key:species
• Key:species:wikidata
• Key:species:de
• Key:species:cs
• Key:species:no
• Key:species:en
• Key:genus:it
• Key:taxon
• Key:genus:en
• Key:taxon:cultivar
• Tag:taxon:family=Arecaceae

External discussions

• https://community.openstreetmap.org/t/rfc-feature-proposal-taxonomic-rank/137216 (Global OSM Tagging general discussion)
• https://community.openstreetmap.org/t/voorstel-introduceren-tag-voor-taxonomische-rang/137259 (Dutch OSM Community)

Comments

Please comment on the discussion page.