[Tagging] seamark:bridge:clearance_height=no_indications

[Mateusz Konieczny]

"not tagging anything at all would convey about as much information"

not exactly, it does not allow to mark that something was checked and surveyed

For example in similar cases (looking for bridges with signed max weight limit)
there are at least following options
- record only signed maxweight (lower amount of used tags, but systematic
  survey for missing maxweight is impossible to coordinate - mappers may
  keep checking the same bridges and completely miss other)
- record also that max weight limit is not signed - maxweight:signed=no
  gets added to bridges without max weight signs but this allows
  systematic survey, for example thanks to this I found that
  https://commons.wikimedia.org/wiki/File:Nad_Zalewem_2019-07-08_17-23-24.jpg
  in a very well mapped area was missing maxweight=2.5
  ( https://www.openstreetmap.org/changeset/71494222 )

It is tricky to decide when it is used to record such data.
noname=yes has quite decent acceptance 
( https://wiki.openstreetmap.org/wiki/Tag:noname%3Dyes ),
tagging maxweight:signed=no on every road (not only bridges) would be silly etc...

Though I encountered mappers who wanted to remove noname=yes
as pointless clutter and ones who wanted to add either oneway=yes
or oneway=no on every single road.


Aug 7, 2021, 18:25 by tagging at openstreetmap.org:

> Absolutely agree, StreetComplete would have to check whether the underlying waterway allows for ship traffic before tagging. Really not sure how “unknown” ever came into existence, not tagging anything at all would convey about as much information.
>
>
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Wednesday, August 4th, 2021 at 1:30 PM, Mateusz Konieczny via Tagging <tagging at openstreetmap.org> wrote:
>
>
>> In my opinion it is a good idea for a tag.
>>
>> Though it should be only added in case of waterway marked as usable by boats
>> or with some indicator that would be likely usable for boats.
>>
>> It should not be used for every single drain, stream and other minor waterways.
>>
>> =unknown is unclear as it may be both "not checked"/"not verified" and
>> "not signed"
>>
>>
>> Aug 4, 2021, 11:43 by tagging at openstreetmap.org:
>>
>>> Hi everyone,
>>>
>>> Over on the StreetComplete GitHub page <https://github.com/streetcomplete/StreetComplete/issues/2929>>>>  we've been discussing support for seamark:bridge:clearance_height=* and associated tags. This tag concerns the space that ships have to pass under bridges. Often, there are signs next to bridges indicating to ships what this clearance is. One question we're facing is what to tag if there is no such indication of clearance. >>> Taginfo tells us  <https://taginfo.openstreetmap.org/keys/seamark%3Abridge%3Aclearance_height#values>>>> that "unknown" is used in practice in such cases, however, I suggest using "no_indications" for StreetComplete, similar to the >>> "maxheight" key <https://wiki.openstreetmap.org/wiki/Key:maxheight#Non-numerical_values>>>> , as it conveys more accurate information than "unknown" does. Neither "unknown" nor "no_indications" are currently mentioned on the relevant >>> wiki page <https://wiki.openstreetmap.org/wiki/Seamarks/Bridges#Clearances>>>> , and before introducing this value, we wanted to run it past this group for feedback. Bear in mind, this is not a suggestion to mechanically replace all "unknown" values with "no_indications", just a suggestion of a new value.
>>>
>>> I'm looking forward to your feedback!
>>>
>>> Kind regards,
>>>
>>> Tomagori
>>>
>>
>>
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20210808/29f1f13a/attachment-0001.htm>