[Tagging] what does maxheight=none mean?

mmd mmd.osm+tagging at gmail.com
Mon Oct 27 20:21:09 UTC 2014

Am 27.10.2014 um 13:11 schrieb Richard Welty:
> On 10/27/14 6:45 AM, Tom Pfeifer wrote:
>> You are quoting me out of context, leaving the impression that I'd
>> propose
>> to tag the bridge way, this is not the case.
>> I was just pointing out that tagging the way under the bridge makes
>> no explicit reference to the bridge itself, and can lose the implicit
>> proximity reference when the way is split. An explicit reference would
>> need a relation.
> since the height restriction only applies to the segment of road directly
> underneath the structure, i have always been careful to split the way
> on either side, fairly close to the structure before adding the tag.
> it seems like the only sensible way to do this.

If a legal maxheight tag only affects a tiny section underneath a
structure, an alternative might be to add a dedicated maxheight node to
the road in question like in case of [1].

For the purpose of identifying missing maxheight tags, I will also check
for maxheight nodes in close proximity to a bridge (see analysis [2]).

If you look at A428 'Crick Road' with its two railway bridges you can
spot the difference: the missing maxheight tag is highlighted for the
railway bridge without a maxheight node underneath.

I implemented this 'node' option after some mappers complained about the
overhead of splitting up a road just for the sake of adding a
maxheight=default or maxheight=none tag.

Of course, the situation is different, if a larger section of a road has
an explicit legal maxheight limit. Splitting up the road in that case
seems unavoidable.

BTW: Please disregard the relation on node 1686139306, I don't use it
for my analysis.

[1] http://www.openstreetmap.org/node/1686139306
[2] http://tinyurl.com/mu9oqrg

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