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

[Martin Koppenhoefer]

2015-02-16 10:42 GMT+01:00 Martin Vonwald <imagic.osm at gmail.com>:

> Hi!
>
> I just stumbled upon the wiki article regarding maxwidth:physical. From
> reading it - and the articles about maxwidth and width - I don't really
> understand when to use each key.
>
> My understanding so far:
> * width: this is the actual width of a feature
>


+1



> * maxwidth: this is a legal limitation; nothing wider than the given value
> may use the feature
>


+1, there is also the synonym "maxwidth:legal" (IMHO not advisable, as this
is the same than the more used "maxwidth")



> * maxwidth:physical: according to the wiki page: a physical limit
>


IIRR there were users of latin american countries telling that their
bridges sometimes had 2 height informations signposted: maxheight and
maxheight:physical and that this was the reason for the introduction of
maxheight:physical (I assume that maxwidth is working just the same).



>
> The width of a feature in my understanding is a physical limit.
>


-1, the "width" is one dimension of a feature (depending on the kind of
thing you are describing, there are other dimensions like height, length,
diameter, depth, etc.), I wouldn't call this (in all cases) a "limit"



So when should maxwidth:physical be used? One example I can think of might
> be a way with varying width, i.e. it is not possible to specify "width" and
> maxwidth:physical should be used to specify the minimum width along the
> way. Another one might be the maximum width of a vehicle, that may pass a
> barrier (this is indicated in the first sentence of the article).
>


if there was something tagged like (example made up):
barrier=bollard
width=0.2m
maxwidth=1.2m

I'd expect the width to be the width of the bollard and maxwidth the (in
theory "legal") width of the vehicle that can pass through (e.g. number
taken by reading off a sign) and you might want to add
maxwidth:physical=1.22m (the actual maximum width of a vehicle or person
that can pass through).


cheers,
Martin
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