[Tagging] Tagging type of ownership of a road

[stevea]

On Apr 13, 2023, at 3:11 PM, Graeme Fitzpatrick <graemefitz1 at gmail.com> wrote:
> On Thu, 13 Apr 2023 at 20:48, Greg Troxel <gdt at lexort.com> wrote:
>  (admin_level 4/6/8, normally).
> 
> Would it work to add the admin_level= to the road to say which level of Government owns it?

No, it wouldn't.  It would add confusion and ambiguity to what is meant by "admin_level" which is difficult enough that it should be left alone to denote what it purports to denote now.

I have sought a similar sort of tagging in regard to parks, where I coined / developed / wiki-discussed [1] a tag which sought to eventually allow renderers to choose a line color to draw the outline of a park boundary in a particular color (e.g. national parks, denoted park_level=2 could be green, "county" parks, denoted park_level=6, could be blue or red or whatever...).

This never really went anywhere except ideas and informal (up to and including wiki) discussion — perhaps there was no great call for "multiply-colored park boundaries rendered to indicate their level of government administration."  That's OK.  But it is still a useful concept, and one which could springboard into what might be ideated here:  that "ownership of a road" could be indicated by something like a rendered color (or casing, or hatching, or whatever).  If a tag were coined like "road_level" (where its values correspond to admin_level values, but are not called admin_level), I think OSM could be much closer to achieving the desired objectives without potentially sowing confusion and ambiguity with the already-sensitive-to-document admin_level (and its carefully constructed values — please let's leave those alone as both "fragile" and yet "holding together" as they are right not).

> Then I would think that a search should be able to say that this is an AL2 highway in the country of Norway, so owned by the Norwegian Federal Government; while this intersection is of an AL4 primary & an AL8 tertiary road, therefore belonging to this "State" & this "City"?

A search might be able to discern "in which" jurisdiction(s) a road is found, much like a geocoder works with a minimal amount of data "scattered around" (geographically) enough to determine "close enough to a node to be associated with it" (as a place, for example), or "inside the polygon that denotes a particular municipality."  Those are working strategies for geocoders and a minimal amount of tagging data to "feed" them, and similarly, we don't want more than the minimal, necessary amount of data about road ownership, too.  Where it is has already been encoded merely by the fact of its geographic coordinates of where it is in the map.  We don't need to redundantly add these.  Something like "private, municipal, county, regional, state, national / federal" or whatever as values to a well-chosen tag, yes.  That can work.  (And look how "is_in" is now seen as superfluous and deprecatable for the same reasons).  Simultaneously proposing something like "road_level" to help in rendering, well, that could be a good idea, too, if people want the downstream (e.g. renderers) to benefit in a pretty way.

Finally in this discussion, it almost is never a good idea to throw in the word "type" (as in the Subject) when it isn't necessary:  it can only add to more confusion.  I'll know what is meant (and so will others) as "Tagging ownership of a road" is discussed, without adding the word "type" to the dialog.

Thanks for reading.

[1] https://wiki.osm.org/wiki/Key:park:type#park_level=*
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