[Tagging] Best practices regarding implied tags

[Joseph Eisenberg]

The previous responses are focusing on the benefit of adding explicit tags
in situations where the current tagging is ambiguous.

Certainly there is a benefit of adding "oneway=no" on all two-way roads and
"oneway=yes" on motorways to make the situation explicit.

But the original question was about whether or not we should add
"man_made=utility_pole" + "utility=power" to current power poles.

These are currently tagged "power=pole" which is clearly defined as a power
utility pole, so adding the two other tags does not provide any information.

Does anyone think that it is a good idea to add those two new tags in this
particular situation?

-Joseph Eisenberg

On Sun, Sep 20, 2020 at 9:46 AM François Lacombe <fl.infosreseaux at gmail.com>
wrote:

> Thank you all for replies
>
> Then the current proposal sounds to be ok regarding what is said upside.
> I admit to automatically adding implied tags when importing data covered
> by the proposal, so no apparent problem is mappers add them explicitly.
>
> All the best
>
> François
>
> Le jeu. 17 sept. 2020 à 15:11, Kevin Broderick <ktb at kevinbroderick.com> a
> écrit :
>
>> +1.
>>
>> Explicit tagging indicates a level of confidence not generally associated
>> with implicit tagging. While there's certainly an 'ad nauseum' level of
>> doing so (e.g. adding surface=paved, motor_vehicle=yes to highway=motorway
>> in the U.S. would be kinda silly, IMO), there are plenty of cases where a
>> primary tag generally implies something about the tagged object but doesn't
>> guarantee it. I'd point to the recent discussion of access= on driveways as
>> an example; while most driveways allow for certain types of access by
>> default, it's far from guaranteed—there may be a no-trespassing sign or a
>> locked gate, and explicitly indicating the lack of such in the access
>> tagging is helpful. (Adding the implied value without survey or other
>> definitive knowledge is not, as then you express a higher degree of
>> confidence than actually exists in the data).
>>
>> On Wed, Sep 16, 2020 at 6:34 PM Paul Johnson <baloo at ursamundi.org> wrote:
>>
>>> On Wed, Sep 16, 2020 at 5:20 PM François Lacombe <
>>> fl.infosreseaux at gmail.com> wrote:
>>>
>>>> Is that completely wrong or mappers could eventually add implied tags
>>>> if they want to?
>>>> The proposal currently states they are optional and it won't raise an
>>>> error if mappers add them beside mandatory tags.
>>>>
>>>
>>> No, it's not wrong to add implied tags explicitly.  It's actually
>>> encouraged in some cases where the implicit tag is not consumable by
>>> automated system (such as the "none" default for turn:lanes tends to be
>>> ambiguous between "you can't turn from this lane" and "you can't use this
>>> lane" and "there's an implicit but unspecified implication that isn't
>>> painted on the ground"), or access defaults (such as in the US where
>>> bicycle=* and foot=* varies a lot on highway=motorway)
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>>
>>
>> --
>> Kevin Broderick
>> ktb at kevinbroderick.com
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