[Tagging] Feature Proposal - RFC - crossing:markings

[Minh Nguyen]

Vào lúc 15:19 2022-07-10, Marc_marc đã viết:
> Hello,
> 
> Le 10.07.22 à 23:48, Alexander Kane a écrit :
>> but not replace any of the existing schemes. 
> 
> first of all, thank you for your courage (or naivety) to spend time on 
> this problem.
> So you are proposing an additional scheme, another layer on top
> of the many existing variants?
> I don't see the point, what is needed is to reduce the number of 
> schemes, not to add more.
> 
> For the moment we have :
> crossing=zebra in England which means crossing=uncontrolled (approved 
> tag) + crossing_ref=zebra
> crossing=zebra outside of England listed as a controversial iD decision 
> and which according to contributors means crossing=uncontrolled 
> crossing_ref=zebra or crossing_ref=zebra
> crossing=marked controversial decision of iD which overwrites/loses the 
> information of the 2 approved values crossing=traffic_signals <> 
> crossing=uncontrolled, depending on contributors and preset versions 
> this can imply crossing=uncontrolled or not (the french version of the 
> iD preset has long spoken of "marking on the ground")
> marking=zebra which could replace crossing_ref=zebra with a more 
> meaningful name, but maybe not in all country (see other UK specific name)
> and now yours which would not override any of the previous versions

The current state of crossing classification is not simply a story of 
good approval versus bad editor. [1] Insisting on a return to approved 
tags in response to a proposal for new approved tags strikes me as 
circular reasoning. As the proposal points out, crossing_ref has been 
overloaded: apparently American zoos breed a different kind of zebra 
than European zoos. There are some other practical issues beyond 
markings, such as the unmarked-signalized configuration being regionally 
standard and commonplace but inexpressible. [2][3]

> imho the only good solution is to start by removing crossing=zebra and 
> replace it in England (and other countries with the same traffic rules) 
> by crossing=uncontrolled (approved tag) crossing_ref=zebra, and outside 
> England by crossing_ref=zebra
> when it will be eradicated, we will see more clearly

Setting aside how crossing=zebra came to be, its more fundamental 
problem is that the tag cannot be taken at face value. It comes with 
implicit connotations that end up causing disagreements when applied to 
different traffic rules. This same problem affects 
crossing=traffic_signals and crossing=uncontrolled. A single 
classification-like key tries to create order where none can be 
guaranteed, so all the recent proposed solutions for this problem have 
required introducing explicit subkeys.

I welcome crossing:markings and look forward to using it in conjunction 
with the proposed crossing:signals scheme. [4] But I agree that this 
proposal should not keep such a light touch. Deprecating the mess of 
existing tags would force us to really consider the best way to describe 
crossings. Not deprecating existing tags just proliferates mapping 
styles, putting innocent mappers in the middle of these disagreements.

Somehow railroad crossings managed to escape the trap of shortsighted 
classification tagging. The rail regulators in my region classify level 
crossings on a linear scale. For example, the presence of flashing 
lights **of course** implies a bell, a saltire, and the requirement for 
the train to blow its horn. [5] But I see no problem in filling out a 
detailed form about crossing:saltire, crossing:bell, crossing:light, and 
crossing:horn. The extra checkboxes benefit regions where these 
fundamental laws of the universe do not hold. There can always be a 
preset for each common combination for mappers' convenience.

[1] 
https://wiki.openstreetmap.org/wiki/Special:PermanentLink/2340404#Street_crossings
[2] https://github.com/openstreetmap/id-tagging-schema/issues/408
[3] https://github.com/openstreetmap/id-tagging-schema/issues/507
[4] https://wiki.openstreetmap.org/wiki/Proposed_features/crossing:signals
[5] 
https://wiki.openstreetmap.org/wiki/Special:PermanentLink/2320689#California_Public_Utilities_Commission

-- 
minh at nguyen.cincinnati.oh.us