[Tagging] what does maxheight=none mean?

moltonel 3x Combo moltonel at gmail.com
Mon Oct 27 10:04:18 UTC 2014

On 27/10/2014, Holger Jeromin <mailgmane at katur.de> wrote:
> Tom Pfeifer wrote on 27.10.2014 10:20:
>> As said before I am not against keeping a record of a bridge being
>> checked,
>> just the value =none is misleading.
>> Another problem is that the tag is on the way under the bridge, and
>> not the bridge way itself. That leads to the situation that somebody
>> tags a 15km motorway because one bridge is unsigned. The next mapper
>> splits the way to tag some turn:lanes, and thus creates segments
>> of the road where there is no bridge at all.
> So what?
> This tag indicates that the segment of the street is checked and there
> is no legal limit visible.
> If this situation comes from a mapped bridge or some other (unmapped?)
> thing is no difference.
> It says: As a mapper i do not have to walk there and check the sign, as
> someone has done it (and found none).

The maxheight=* tag maps the physical limitation, not the sign (which
can be absent or even wrong). Tagging maxheight=none really makes no

I'd even argue that tagging "I surveyed this but couldn't see a
limitation" is useless: the sign might get added later, some mapper
might be able to measure the maxheight, the value above 4m might be
important for some people, etc. Don't try to silence the QA tool when
there actually is a bridge with a physical maxheigth.

> QA tools should only check ways under a bridge for this tag, but should
> not warn if this tag is at an way without a bridge.

Tagging maxheight=* on a long way instead of just around the bridge is
bad tagging for two reasons, which justifies QA checks :
* It can prevent routing to a property near the bridge
* It can lead to mapping errors when the way is split, a bridge is
added somewhere else, etc.

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