[Tagging] Route maintenance tagging

[Kevin Kenny]

On Thu, Jul 19, 2018 at 7:22 AM Peter Elderson <pelderson at gmail.com> wrote:
> The goal of the idea is to tag the date of the last reality check. The best thing I have now is the date of the last edit, which most of the time results from e.g. a mapper's action (cut or remove) on a way that's part of the route relation.
>
> I want to ensure that the route in the field and the route relation stay in sync, and when they don't (which is a 100% certainty) that you can tell at what point in time it did match.
>
> Information older than that date (e.g. gpx-tracks) can be discarded, newer information can be entered, and edits after the survey date are new info which should be kept.

Keeping the field survey up to date is a laudable goal, and I've no
objection to some sort of tagging that reports "this geometry was
field surveyed on <date>." Making it fit with the data model will be
challenging; it's not something that can be easily automated, given
the variety of mappers' workflows.In the current world, to make
something like this a reality you have to have an individual or
organization that becomes the de facto 'owner' of the route and keeps
track of its own surveys - and that isn't very OSMish. I think this
could be worked around with sufficient cleverness.

But please, please, don't discard data older than a certain date. OSM
is a very young project as geography goes. While out-of-date data can
be misleading, the right thing to do is to inform, not to delete,
particularly in cases where the out-of-date information is the only
information that is available. It may also be the only information
that can guide in recovering from an act of vandalism or a
badly-considered import.

Perhaps I'm coming at this from the 'wrong' perspective. since a fair
amount of my mapping is of features that nobody has yet seen fit to
map at all, or that were once imported from external data that I
consider hallucinatory. If someone with a GPS found a route passable a
decade ago, that's a piece of information that I now have that I
wouldn't have had otherwise. It could be that the route is no longer
passable, has been relocated, or has been demolished, but without the
old data, what reason do I have even to go and find out?

Moreover, the land remembers. I've been on trips where abandoned
tracks and the grades of dismantled railroads, a century old and now
grown to trees, have been important landmarks. I have no qualms about
not showing them on a general-purpose map, but to an off-trail hiker,
they are waymarks for eyes to see that can.

The right thing to do with 'stale' data - perhaps even 'proven
incorrect' data - is to inform, not to discard.