[OSM-talk] Map Features tagging question

[Nicola Ranaldo]

On Thursday 20 July 2006 10:28, Andy Robinson wrote:
> No, you are absolutely right, nearly everyone wishes to see a level of
> consistency. The trouble is not everyone wants to use the OSM data for the

[...]

> tags that are already there. Existing tags should never be deleted if
> possible in case they are being used by someone.

From a developer point of view:

* when a user enter a tag for an osm object, this information is available for 
everyone in the world
* this information should be useful for the community and not for private 
needs (use your hard disk for that :))
* this information in the 99% of cases will be used by the software and not by 
humans!
* the software does not know the human meaning of a tag but has to follow a  
well-defined set of rules

==>

* you should enter data in osm if well defined!
* you should fix data in osm if not well defined!
* before adding an undocumented tag in the system post an rfc on the 
mailing-list

If this is against the freedom (to construct an unusable data set?), we should 
separate tags in "namespaces", and reserve an XXX official namespace only for 
common rendering/viewing/routeplanning where data integrity is strongly 
enforced. Other namespaces could be free (to construct private data set?) if 
we really need them. Editors and viewers could be free or XXX compliant.

The same concept should be applied to data primitives, we should strongly 
define them and enforce data integrity on the database, for example the id is 
an integer > 0 and in the osmplanet there are ways with segs with a negative 
id. Are two segments from x to y and from y to x admitted? Are two nodes with 
the same lat,lon admitted? Actual editors take care of those?
As specified in the "Data Primitives" wiki page, ways and areas are objects 
with the same elements. Is necessary to separate them? If not what are the 
differences? these are simple examples, but while coding osm "clients" they 
affects data structures more then a bit, and shows strange paths when doing 
route-planning!

	Niko