[OSM-talk] Trying to find a solution for country specific and defaults values

[sylvain letuffe]

Hi,

We all know osm cover the world, we all know that defaults values are 
different from country to country and some of us know this is a monster pain 
to make a world wide routing program, a world speed alert tool or any world 
wide tool that need to know : "what do we have here".

The tag set, is currently constructed as being a "as close as possible" as the 
common denominator (or maybe close to the UK case )

Some pages 
http://wiki.openstreetmap.org/wiki/Country_specific_default_values
try to list those defaults "just in case"

Some pages  (mine)
http://wiki.openstreetmap.org/wiki/Talk:Proposed_features/Any_moving_thing_grouping_system
says we shouldn't assume there are defaults

Once uppon a time I thought we should tag EVERY thing
( highway=motorway foot=no horse=no mopped=no oneway=yes 
maxspeed=120 ............. )

Solutions :
-------------
1) The main problem of what we do, is that it put such a burden on developper 
side that they will just ignore other countries than what they are interested 
in. So we just have hope that someone will help them.

2) We could ask mappers to tag every thing, but that will put such a burden to 
editors that they will simply don't.

3) we could ask editors developper to automatically add the appropriate tags 
given that the mapper is mapping only one country and that he had given it in 
a input box.

4) we could feed the missing database tags with all possible tags based on the 
polygone country they are in, filled with default values

2 has no sense, it will never been done, 3 and 4 will create such an enormous 
database that editors interface will become useless. and creating an false 
idea that something has been tagged.

1 is what we do (I think), but it makes it even harder for people with "few" 
time to create a good tool that is valid worldwide, developpers have to 
constantly watch at wiki, some intersecting tags will not be covered,...

I have a plan for option 5) wich I don't know if it is better.

Something between the perfectly valid 2 and the easy 1 :

- create a tool that will post-process osm files to include any "relevant" 
tags so if a developper just respect the global hierarchy, his tool will work 
on the whole world.

I strongly suspect that developpers all do that a bit in their software 
(mkgmap, routing, rendering, ... ) so losing extra time, and finishing in not 
perfect worldwide tools.

Quick examples :
- add motocar=no to all german tracks
- add oneway:foot=no to all oneway=yes
- add mopped=yes to all $country's motorway
- add bicylce=no to all UK pedestrians
- add maxspeed=90 km/h to all french primary/secondary
etc.

Other idea, not related to country :
- add access=no to all disused=yes
well, add implied defaults to make them explicit. And over all for new coming 
extra specific tags where the routing programm's developper is bored of 
continuously adding modifications

I'am so sorry if such a tool already exists, I haven't found it


-- 
Sylvain Letuffe liste at letuffe.org
qui suis-je : http://slyserv.dyndns.org