On Tue, 24 Aug 2010 10:03:42 +0200 Ulf Lamping <ulf.lamp...@googlemail.com> wrote:
> Am 24.08.2010 09:36, schrieb Ross Scanlon: > >> Well, I will take a change to 'troll' again about it. This discussion > >> comes up again and again because we don't have: > >> a) clear tagging guidelines (*not* rules) > >> b) mechanism to replace tags > > > > Agree totally. > > > > This (b) would be easily recitified by normalising the database in regards > > to tags. > > So how do you easily: "normalise the mappers minds, renderers, editing > software in regards to tags"?!? > > Over several years past now, I have seen this discussions come and go. > When someone was actually doing something, it usually ended up in a mess > of wiki, mappers, editors and renderers disagreeing how to tag > something. A confusion causing a *lot* more harm than any good. > > It's simply a misconception, that just "cleaning up" the tag names will > lead to an easier mapping experience. > > Regards, ULFL You have no idea about normalising a database do you. It has nothing to do with what you have above. Rather than storing a tag as a key=value, you store it as a unique identifier. The identifier is then referenced in another table in the database which will provide the key and value. Lets take an example. Currently in osm we have a road tagged with the following: name="A street" highway=residential source=xyz If the database was normalised then the following would occur. name="A street" tag_id=1000000 tag_id=1000001 The tagging table would have in it: for a tag_id of 1000000 tag_id=1000000 key=highway value=residential for a tag_id of 1000001 tag_id=1000001 key=source value=xyz Now say that we decide that we no longer wish to call residential ways "residential" but a new name of "house streets". To change the current database it would take a lot of effort but with a normalised database all we have to do is change the "value=residential" in the tagging database to "value=house_streets" and every way that was tagged residential is now tagged "house streets". Tags like name would not have a tag_id as they are not unique. The renderers would simply have to look in the tagging table to see what needs to be displayed. -- Cheers Ross _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging
