After ~16 months from this we now have 3⁽¹⁾ specific/specialized/regional validation rules available for JOSM.
Czechs broke our hegemony of Portuguese speaking countries >:-(
But this is very good! It means better tests and possible⁽²⁾ better data in OSM.
Rules can be created for specific countries, areas (both as “knowledge area” or “geographical area”), tags, objects or whatever you want or need.
They could (and should!) be more and I am sure that every OSM community would benefit a lot with custom validation rules for their countries or specific needs.
⁽¹⁾ yes, I know how to count (sometimes, at least); both Portuguese rules should be merged into one in the future
⁽²⁾ possible because validation and testing isn’t magical; it depends on who is analyzing and fixing the problems to have a good result
Comment from dieterdreist on 6 May 2015 at 11:16
A big risk of countryspecific rules (and countryspecific tagging) is inconsistency. One of the benefits of OSM is a worldwide dataset, tagged according to the same system and rules. By changing this we risk of falling apart.
Comment from naoliv on 6 May 2015 at 12:56
Of course we don’t want to create divergence in the data (and people creating validation rules should be aware of this) but we can validate what is known to be different between the countries (usually the free-form tags (name, ref, etc)).
For example, in Brazil: highway’s ref follow a specific pattern that can be matched and validated with a regex. I am almost sure that no other country use the same pattern in ref.
The newly created Czech Republic address system is also another good example: the data is valid (according to the rules and conventions of OSM) but they also have their particular format.
Czech Republic address system
Note that common rules (which could be used anywhere) are usually forwarded to JOSM.