[Tagging] [OSM-talk] Should we map things that do not exist?

[stevea]

On Dec 31, 2020, at 10:11 AM, Stefan Tauner <stefan.tauner at gmx.at> wrote:
> However, I am not convinced that a completely razed railway has to be
> tagged as such. Why would that be the case? If things are removed from
> the world we delete them as well usually. Are there other man-made
> features with long-lasting effects that get demolished (without
> replacement)? (How) Do they get mapped? I have no example but I would
> presume such things exist (that are not historic) like industrial
> plants, mines etc. It might be more advantageous to improve tags that
> describe the remaining effects than mapping non-existent things.

One persistent example are industrial plants that cause a great deal of pollution (often intentionally well-hidden, on-site storage of hazardous materials, or which are clandestinely deposited into the soil).  These firms frequently declare bankruptcy or otherwise divest themselves of the polluted property and vanish into corporate dissolution or similar, leaving the lasting legacy of toxic waste behind.  Sure, the factory / buildings / infrastructure that created and allowed the pollution may be gone, but the need to tag boundary=hazard, hazard=contamination remains.

> Without good replacements though I agree with your strong opposition of
> removing that information from OSM.

Thank you, although I think you are agreeing with Volker, the OP, rather than me, who replied.  (Volker and I agree).  To be clear, there are no "replacements" (existing or proposed) for railway=abandoned (or similar values), there are simply the tags we have already defined, documented and data so tagged which are already in the map.  They belong, they should stay, they can and should continue to be entered where they exist (as a right-of-way, especially when proposed to be included in a "rail-trail").

SteveA