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<div class="moz-cite-prefix">On 3/10/22 22:01, Peter Elderson wrote:<br>
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<div dir="ltr">I would avoid "primary key", because that is a
term from database management systems. It means the
identifying attribute (Id) of an entity, usually a unique
identifier with an index (primary index), used to retrieve
records and to link the entity (table) to other tables.
Something else entirely. </div>
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<div>Main key is better. </div>
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<div>Further: the main key gives the type of object, the main
tag gives a category within that type of object. That is an
important difference, in documentation.</div>
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<p>semantics (nit picking) An OSM 'tag' is both a key and a value,
example {{tag|colour|yellow}}. So it gives both 'object' and
'category'. Ok? <br>
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<div>Feature tag, I think it means the tag that gives the object
type (the main key) and the category within the object type
(the value). So, equivalent to main tag. </div>
<div>I think the term secondary tag(s) and secondary key(s) are
often used for the extra attributes of a feature, implying
there should be a main tag first, to give the secondary tags
meaning.</div>
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<p>If we use 'main key'/'main tag' then secondary key/tag is
logical. <br>
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<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">Peter Elderson</div>
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<div dir="ltr" class="gmail_attr">Op ma 3 okt. 2022 om 12:40
schreef martianfreeloader <<a
href="mailto:martianfreeloader@posteo.net"
moz-do-not-send="true" class="moz-txt-link-freetext">martianfreeloader@posteo.net</a>>:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Thank you all for the
many insightful replies to my question!<br>
<br>
What I've learnt so far:<br>
<br>
1) A feature is something in the physical world. This is
well documented <br>
in the wiki: <a
href="https://wiki.openstreetmap.org/wiki/Features"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://wiki.openstreetmap.org/wiki/Features</a><br>
<br>
2) There is no such thing as a "primary feature".<br>
<br>
3) The terms "main key", "primary key" and "feature tag" are
synonymous, <br>
except for the tag/key distinction.<br>
<br>
4) None of the above terms is official OSM terminology.<br>
<br>
5) None of these terms is well documented in the wiki.<br>
<br>
-------<br>
<br>
It looks like a couple of things would be good to get done:<br>
<br>
A) We should get rid of the term "primary feature" in the
wiki page <br>
<a href="https://wiki.openstreetmap.org/wiki/Map_features"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://wiki.openstreetmap.org/wiki/Map_features</a><br>
<br>
B) It would be useful if we agree on *one* official term for
"main key", <br>
"primary key" or "feature tag". (I think "primary key/tag"
is the most <br>
popular one)<br>
<br>
C) We should document what we mean by this.<br>
<br>
------<br>
<br>
Open questions:<br>
Q1) Which term should we choose as official term? ("main
key"/"primary <br>
key"/"feature tag")<br>
<br>
Q2) Should one OSM object hold multiple "primary tags"?
(ongoing <br>
discussion between Mateusz, Martin, Warin, Marc et al.)<br>
<br>
<br>
<br>
On 03/10/2022 12:16, Marc_marc wrote:<br>
> Le 03.10.22 à 10:47, Mateusz Konieczny via Tagging a
écrit :<br>
>> there are cases where road is going in stream bed<br>
> <br>
> imho only one main feature/objet : the stream bed<br>
> and car use it, a bit like a bicycle uses a road.<br>
> <br>
> but we don't really have a secondary tag to say that<br>
> the stream bed is usable by a car... so we end up<br>
> describing this secondary use with a 2nd main tag...<br>
> this is not perfect<br>
> <br>
> <br>
> <br>
> _______________________________________________<br>
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href="https://lists.openstreetmap.org/listinfo/tagging"
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class="moz-txt-link-freetext">https://lists.openstreetmap.org/listinfo/tagging</a><br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
Tagging mailing list
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<a class="moz-txt-link-freetext" href="https://lists.openstreetmap.org/listinfo/tagging">https://lists.openstreetmap.org/listinfo/tagging</a>
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