On 28 June 2013 11:29, Steve Bennett <[email protected]> wrote: > On Fri, Jun 28, 2013 at 3:23 AM, Andrew Chadwick (lists) > <[email protected]> wrote: > > Mmmm...not quite. You're driving home from work. The bridge you > normally drive over has been demolished. I'd say that's pretty > "physically relevant" to you right now. And tomorrow. And probably for > a few weeks. Maybe months. That bridge that was demolished 6 years > ago? Not so much. It's up to local mappers to decide when to remove > the object altogether.
Do you want it to be unavailable to routing, and also not rendered? Me too, but in that case it's simpler to just delete the object or do something to any tags with understood meaning so they, er, stop expressing something that's now untrue. Physical relevance problem solved. Sure, it's amusing to ponder whether we should retain object identity for moves, like that of the "demolished" (in reality, carefully taken down) and then "rebuilt" (in reality, historic granite stonework cladding on a modern concrete core) https://en.wikipedia.org/wiki/London_Bridge_(Lake_Havasu_City) , but in general we don't do that. Real-world history is not generally preserved in a database object's identity, particularly when materials might be reused in different objects. So perhaps naïvely, I think it's a perfectly valid approach to delete your bridge object from the database and replace it with what it has now become. But you have me guessing. What meaning do you think it adds to an object to say that it's now "demolished"? Do you mean to express its new physical rubble-ness, or capture the feeling of absence of something recently pulled down and new facts about how human beings might refer to it? Either's verifiable, in a way (either look, or ask someone), and either's a meaningful thing to put on a map, in a way. (Talk about psychogeography though! /not-a-request-no-seriously) Perhaps a big black X would be a cute rendering for the latter sort of thing. Give a concrete (as it were) example, tell us more about why it makes sense not to delete the object, but to tag it up specially as a demolished-thing. Some good criteria for when one should *stop* mapping it and delete the object would be good too. Sure, surrounding areas change character when stuff gets demolished. Since demolition doesn't happen in a vacuum - there's often barrier hoarding erected for public safety - and since during demolition the area has a definite steel-toecapped work-booted character, it should probably get a landuse tag. landuse=construction with a phase modifier, or its own landuse=* would suffice. But that's a different concern than that of object identity. -- Andrew Chadwick _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
