[Tagging] Tagging a Portuguese pavement

[António Madeira]

Às 20:40 de 25/01/2021, Fernando Trebien escreveu:
>
>> Technically, in OSM database terms, I don't know what's the difference between a tag and a namespace (I would appreciate if someone could explain this).
> See here: https://wiki.openstreetmap.org/wiki/Namespace
>
> "sett:style" is a tag, "sett:" (the prefix part) is a namespace that
> groups all tags that begin with "sett:". Many namespaces (such as
> "addr:") have their own article explaining more complex tagging
> schemes. Namespaces are sometimes handled differently by tools. For
> example, in JOSM, if you search for sidewalk=left you don't have to
> surround anything with quotes, but if you search for
> "sidewalk:surface"=sett you must surround the tag name with quotes
> otherwise it is considered an invalid expression.
>

I know the difference in terms of wording structure (although I would
argue that "sett:style" is a key, not a tag), but what I would like to
know is the difference between these, besides semantics:
sett_style=portuguese_pavement
sett:style=portuguese_pavement