[Potlatch-dev] feature categories, features and tags currently used in OSM Potlatch2 deploy

[Richard Fairhurst]

To answer both messages at once...

The theory is that we use what Andy has called "editorial judgement" to 
choose the tags for the osm.org deployment. The three main criteria in 
my eyes are:

- Coherence: does it share the qualities of other successful OSM tags 
(verifiable, unambiguous, meaningful, etc.)?
- Precedence: is it an established tag with demonstrated use (could be 
proved via taginfo) among a range of contributors?
- Importance: is it something that many P2 users could find useful?

There is a very obvious set of core tags that come from this.

We have to be pragmatic and not everything will tick all three boxes. 
highway=path, for example, is not in the tradition of OSM tagging with 
its "granular" rather than "meaningful" approach, but has sufficient 
precedence that it has to be included. OTOH smoothness=* breaks 
coherence and does not have enough precedence.

Note that OSM wiki-voting is expressly not a distinct P2 criterion in 
itself, as is documented on the wiki. However, a good tag from the OSM 
wiki process will hopefully be coherent; its 'approval' may lead in time 
to precedence; which just leaves us, just like any other tool developer, 
to assess whether it is important for our audience. Similarly, a big 
showing on taginfo may not be enough in itself (it could just be the 
result of an import), but can go some way to meeting the criteria.

I think these three messages sum the challenge up quite well:

http://lists.openstreetmap.org/pipermail/potlatch-dev/2011-February/000520.html
http://lists.openstreetmap.org/pipermail/potlatch-dev/2011-February/000522.html
http://lists.openstreetmap.org/pipermail/potlatch-dev/2011-February/000524.html

That's the theory. In practice everything is, as ever, subject to "hours 
in the day" and human fallibility! There are doubtless good tags which 
fulfil the above criteria and which are missing from P2; there will be 
dupes, and misclassifications, and so on. These can be fixed via trac 
tickets, patches and git pull requests.

The copy on osm.org is this:
	http://git.openstreetmap.org/potlatch2.git/blob_plain/HEAD:/resources/map_features.xml

which is sourced from here:
	https://github.com/systemed/potlatch2/blob/master/resources/map_features.xml

and note, of course, that there are <include...> elements so you'll need 
to look at some other files too.

For any project with a stated maintainer, there will inevitably be some 
times when the decision falls back to the maintainer - that's partly 
what they're there for. To take three examples of OSM core software, for 
the osm.org Rails port that's Tom Hughes; for JOSM it's Dirk Stöcker; 
for Potlatch 2 it's me.

cheers
Richard