[Tagging] Terminology primary feature, main tag, etc..

[Warin]

On 3/10/22 19:01, Peter Elderson wrote:
> A feature is not a tag or a key, it's an object in the OSM database. I don't know which features are primary, secondary, ... and why. Anyway, the term primary feature is not equivalent to main key or main tag.


Feature = real world object.

Real world features are 'translated' into OSM using tags.

In OSM the real world feature would have a single tag to say 'what it 
is', a highway, a building etc. This would be the main tag (main key + 
main value)

Other tags such as colour, height, elevation as descriptive details of 
the real world feature.

That make some sense?

> Talking about e.g. roads, the main key is highway= because that key defines the feature as a road or road component. Talking about a particular road, the highway=* tag is the main tag because it defines the type of the road or road component.
>
> So main key and main tag are more or less alike, but not equivalent.
Tag to me is the combination of the key and the value .. eg  {tag | 
highway | service }
>
> Feature tag is a vague term. I suppose it means: an attribute of an object, as opposed e.g. to an attribute of a changeset.


I'd try not to use 'feature' and 'tag' together like that, keeping 
'feature' for the real world and 'tag' for OSM.

>
> Mvg Peter Elderson
>
>> Op 3 okt. 2022 om 04:06 heeft Minh Nguyen <minh at nguyen.cincinnati.oh.us> het volgende geschreven:
>>
>> Vào lúc 10:36 2022-10-02, martianfreeloader đã viết:
>>> Hi,
>>> I'm unsure if I'm using correct terminology. I have come across these terms in the OSM ecosystem:
>>> - primary feature [1]
>>> - main key [2]
>>> - primary key [3]
>>> - feature tag [4]
>>> 1) Are these synonyms (except for the key/tag distinction)?
>>> 2) Is *one* of these terms "official" OSM speek with a clear definition?
>>> (as is the case for things like "node", "way", "relation", "key", "value", "tag", "changeset")
>> "Primary feature" appears in the Collective Database Guideline Guideline [sic] and Geocoding community guideline, which clarify the terms of use under the ODbL. [1][2] "Feature type" appears in the Horizontal Map Layers community guideline. [3]
>>
>> [1] https://wiki.osmfoundation.org/wiki/Special:PermanentLink/3980#The_Guideline
>> [2] https://wiki.osmfoundation.org/wiki/Special:PermanentLink/4907#How_does_the_guideline_relate_to_other_existing_guidelines?
>> [3] https://wiki.osmfoundation.org/wiki/Special:PermanentLink/3982#The_Guideline
>>
>> -- 
>> minh at nguyen.cincinnati.oh.us
>>
>>
>>
>>
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