Undocumented usage of side=*

Martin just fixed an issue in iD with the use of the “side” key used for highway=cyclist_waiting_aid objects, see don't reverse `side` tag of highway=cyclist_waiting_aid features, fix… · openstreetmap/iD@85f4cc0 · GitHub

That prompted me to quickly check taginfo, which shows ~70’000 uses of the key of which only ~500 are for waiting aids and the rest seem to be used with traffic_sign objects, likely from traffic sign presets, which contain

<combo key="side" text="Side of the way"  values="right,left,both,up,down"  default="right"/>

which contrary to the direction key seems to be totally undocumented. That alone wouldn’t be an issue, however there are implied semantics that indicate that when the key is used together with traffic_sign and is a way node, the values should be reversed when the way is reversed. Any keys that require special handling really really need to be documented.

Interstingly there is a documented way to desribe exactly this, but for railway signals.
They use railway:signal:position=* instead of side.

This is also related to a recent mass edit that has subsequently turned into a tagging proposal:

To be fair the proposal, including this usage of side=, has existed since 2017.

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Finding my notes I have started to use side=* in that way since 2013. After the adaptation of the Roadsign plugin of JOSM to a Spanish preset I have started to think about how to tag a traffic sign then.

You can read here.

I have tried to use it far away in JOSM, making a first preset and style (I didn’t have the control of Roadsigns to make the updates) and I have preferred myself to start learn how to do a preset, and all the other possibilities, including a style also for JOSM and the only 3D feature I have found was Kendzi3D. As Kendzi modified its plugin to locate relatively to the way a model and oriented also in a correct way with forward and backward, left and right, I have done the first model and Kendzi helped me to do this with Blender (his unique model read the national code of the traffic sign tag and it showed it in Kendzi3D plugin, also with the possibility of configure entire libraries of types of traffic signs based on its shapes.)

Also we talked about that in the forum…10 years ago

Probably the sentence I have read in the wiki many years ago is this:

“As value
Forward, backward, left and right are also sometimes used as a tag’s value. In this case, no additional namespace is added to the key of the tag”.

You can find it in Forward & backward, left & right - OpenStreetMap Wiki

As I have reviewed other argumentations the use started in 2013 based also in these pages of the wiki:


Then ,after finishing main presets,libraries for Kendzi and styles (from 2013-2017) also I have started to document it via taginfo projects and made a page in the wiki (the first proposal in 2017).

Adding just a fraction of the text you just posted to the wiki would have avoided the tag being usurped by a proposal applying different semantics https://wiki.openstreetmap.org/wiki/Key:side.

PS: unrelated keys using documented left and right variants does not create a documentation of a side key.

I have used the tag since 2013 when I have reviewed the wiki and read all that it was written about direction and “side”. You can think about it was the wiki then and how it was OSM then. It is not my problem or my fault if someone does not read the wiki (this part of the proposal from 2017 had not changed since then), taginfo, tagging list (read my mails about that, -my interventions are probably about the same topic- ) or other tools to establish a tag.
After 40 presets, and 12 styles, and 5 groups of models libraries for Kendzi3D, I’m realize that I’m not will be treated the same as other software conflicts (find the approval to crossing=marked or traffic_sign:direction, thanks).
But it is not a big problem for me, if someone has “stolen” a key, or not need the approval of the community, good for him. I’m not a programmer, I’m a school teacher and I’m only want to map traffic signs in a extended way, since 2013, using the methods other did in some parts (Finnish Community, German Community). Now with national id’s -like multivalue proposal- and also human readable values (as other approved proposals do like hazard). Please, Can I?