[OSM-talk] Worldwide non-surveyed tag edits

[SomeoneElse]

An OSM user seems to be on a mission to replace a large number of the 
low usage tags in OSM - mostly in Europe, but also elsewhere:

http://www.openstreetmap.org/user/Markus59/history
(hit "load more" a few times and you'll see the extent of it).

Let's leave aside for now the issue that in some cases tags are being 
replaced with others that simply do not mean the same thing:

http://www.openstreetmap.org/changeset/22839601
(that example has been reverted; I'm sure that other similar ones will 
have been too)

I'm talking here about less problematical changes - things like this:

http://www.openstreetmap.org/way/243539765/history
(car_repair=MOTs to car_repair=MOT)

Let's assume, for the sake of argument, that the latter is the "more 
correct" (or at least more common in OSM); what then is the problem with 
changing it automatically?


Well:

1) People may well be expecting the previous form in OSM data that 
they're using to make maps with.  Whether it's "right" or "wrong" is 
irrelevant; if data no longer appears in selections from extracts of OSM 
data it looks like it's been deleted (this is similar to what happened 
with the "substation/sub_station" JOSM farce and the standard map 
stylesheet - data disappeared from maps for no good reason).

2) Mappers creating the "incorrect" data will continue to do so until 
they're told otherwise.

3) There's an explicit policy designed to prevent edits being done in 
this way:

http://wiki.osm.org/wiki/Mechanical_Edit_Policy

precisely to avoid problems (1) and (2).


So does this mean that tags in OSM can never change?  Of course not - 
mappers who are using "rare" tags to tag exactly the same thing as a 
more common tag simply don't know that the more common tag exists (I've 
done exactly that myself with "outside_seating" and 
"barrier=horse_stile").  If data consumers know that tag X is to be 
replaced with tag Y, they know to change what they extract.  Someone who 
suggests, as per the Mechanical Edit Policy, that car_repair=MOT and 
car_repair=MOTs be united in one tag (or other similar change) is not 
going to be met with any resistance - provided that data consumers have 
fair warning, of course.


I've previously tried to contact the user concerned, but I think that 
it's fair to say that communication did not occur. They tried to 
instruct me in the meaning of the English word "cobblers" based on their 
understanding from a German web-based dictionary; I ended up quoting 
Brewer's back at them. More seriously, my suggestion that there should 
be discussion before worldwide tag edits and that the particular changes 
that I'd contacted them about were just plain invalid fell on deaf ears.


Cheers,

Andy