On Fri, 24 Jul 2020 at 21:28, Jmapb <jm...@gmx.com> wrote: > On 7/24/2020 7:12 PM, Cj Malone wrote: > >> OSM does not store edit timestamps for individual tags, only for the > >> object as a whole. Finding out when a tag was changed requires a > >> review of the entire history. I had to do this once when I saw a > >> clear highway=motorway_link tagged as highway=motorway, with me as > >> the last user to edit that road segment. Turns out the original > >> mapper was the one to make the tagging mistake, not yours truly, but > >> I only found this once reviewing the history. > > > > Yeah, that option would require a new API and work done on the OSM > > server to both calculate the last time a tag was edited, serve it and > > store the timestamp when "touched" or updated. But once that's done > > it's done for multiple clients, not just StreetComplete. > > > > Otherwise StreetComplete would need to use the History API one each > > individual nwr and try to calculate the age of a tag. > > It sounds to me like what you're describing would require not just a new > API but a change to the database schema to add a datetime field to each > tag. Otherwise there would be no way to encode the timestamp of the > confirmation of an existing tag that does not need changing.
That would be essentially the same thing as what's being proposed with check_date-like tags, except at a lower level of abstraction. Might be faster and available to more apps/for more purposes. But on the flip side, of course new API versions and database fields are a much more major change than a new tag scheme. > The history API will only tell you when tags change. Well, a new API endpoint _could_ automatically read through the entire history of a node and note which tags changed when. It would essentially be doing what I do when I open the node history in JOSM and look when tags changed - only automated. That might well be faster in the API, where database accesses and data processing is faster. It would be slower than a dedicated database field, but would not require the database migration. --Jarek _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
