[OSM-talk] Map Features tagging question

[Nicola Ranaldo]

On Thursday 20 July 2006 20:48, you wrote:
> Nicola
> I've been promoting the idea of namespaces for some time.  When I create
> tags which are for my own personal use, and not have any specific meaning
> to anyone else then I prefix them with my user Id.

Yes this is a good practise,  howewer why did you upload them to osm and not 
keep them private?
Do you share your photos with a big set of osm users so they take benefit from 
your tagging?
I'm just curios becouse this is only a database space problem, let's do 
another example.
In a previous message i asked for a "official" key/value system helping 
software rendering of objects names. Answer was that the software has to 
evaluate them without any help. So i was surprised when in the last 
osmarender version there is a special tag "name_direction". 
I think in few time in osm data repository there will be a lot of those.
Well this tag does not appear in the Map Features page.
If OSMF will decide some day to accept the old idea to help rendering software 
and formalize a boolean name_direction tag with value "reversed", data will 
be inconsistent.
If OSMF will decide to update all tags name_direction and apply "reversed" 
where the values is "-1" all the osmarender installations will break! 
If OSMF will decide to leave them unaltered you'll have to modify osmarender 
to handle the "reversed" values too.
This is an academic  case,  where the impact involves a lot of users, it could 
be useful to create a namespace for osmarender, and transform the keys 
in "osmarenderer:name_direction".
OSMF could decide to make name_direction tag official supported, in this case 
i think it would be better software follows OSM and not viceversa :)
The same if OSMF adopts an official different tag, and more users will be 
confused!
In my software i'm writing code to hide place names where zoom level is low.
I want to classify them about population, in map features there is no such 
tag. May i create a "population" tags!?!? may i use a so important tag?  
wath's the real freedom limitations? I could convert geonames to nodes adding  
population tags and uploading them to osm. I'm sure the next day there will 
be a flame on the mailing list :) Pheraps if my software, "OSMNavigator", 
will use a "osmnavigator" name space and i use "osmnavigator:population" 
and "osmnavigator:name" tag i will not offend anyone.
Howewer if a lot of nodes created with geonames import will coincide with 
already existent nodes someone may have problems (i don't know if osmeditor 
or josm or online applet manage nodes with the same latitude, longitude and 
different id). But if you specify that "no duplicated nodes are admitted by 
latitude, longitude", i MUST modify my import script to avoid creation of new 
nodes when already esists and limiting it only to add the osmnavigator:  
tags. My freedom will be the freedom to not impact on other users becoming 
anarchy.
These are only some reasons why i think the project needs a strong 
formalization.
Actually i decided to add a "layer" to my application keeping big data imports 
private, order nodes by town "official" classification and drawing them using 
a "bounding box" collision detector. I have to implement a spatial partition 
index to make things fast, or to add a "visibility scale" column to my 
database and patching the editor code to keep them updated.
You can see how much a decision may impact on software developing.
It could be easy for me adding visibility tags, and have good rendered map for 
me, but somewhere other developers may encounter the same problems and decide 
to adopt other tags, and so on!

I'm sorry for the above examples may offend someone, i respect your work and 
think this is a great project,  I'm just curious to understand better the 
philosophy of the osm world, resolve the problems i'm encountering while 
coding my tool, and hope i can do route planning calculation with maps from 
other users and not only my map!

	Niko