[Tagging] maxwidth vs. maxwidth:physical vs. width

moltonel 3x Combo moltonel at gmail.com
Wed Feb 18 13:38:16 UTC 2015

On 18/02/2015, Tobias Knerr <osm at tobias-knerr.de> wrote:
> On 18.02.2015 10:39, moltonel 3x Combo wrote:
>> Allow me to disagree:
>> * maxheight is defined this way. Having maxwidth defined differently
>> is asking for trouble.
> I agree with you that we should define all the max* keys in the same
> way. But it would actually make much more sense to achieve that
> standardization by reserving them all for legal restriction. Look at the
> current situation:
> maxwidth:
>  legal limit according to all sources
> maxspeed:
>  legal limit according to all sources
> maxweight:
>  legal limit according to all sources
> maxaxleload:
>  legal limit according to all sources
> maxheight:
>  legal limit according to infobox,
>  min(legal,physical) according to introduction text
> The odd one out is clearly that introduction of the Key:maxheight page.

Fair enough, except that :physical doesn't make sense for speed, and
is pretty much impossible to measure for weight and axleload (or
rather the engineers calculated it, and the legal people took the
value verbatim). Because of that, legal == min(legal,physical) for all
those, so it doesn't make any difference and the simpler phrasing
wins, but the min(A,B) phrasing would be just as accurate.

maxspeed is actually much more complex, with lots of subkeys, and a
routing engine (for example) probably has to take many of them into
account. So a naive rule like maxspeed = min(legal,practical) would
not make sense.

Legal vs physical does make sense for height and width. The fact that
only height got an updated wiki page certainly comes from maxwidth:*
being basically unused.

As you point out, reverting the definition of maxheight to mean
maxheight:legal would make the wiki pages look more consistent. But
it'd make the data less usable. You go ahead and tell the owner of a
damaged vehicle that his satnav should have taken both
max{height,width} and max{height,width}:physical into account, I
prefer to avoid this using the min(legal,physical) definition.

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