[OSM-dev] Relationships - working prototype

[michael_j at email.de]

> A lot of detailed changes have been suggested and I'll read  
> everything and try to make it into a "version 2 prototype" which I'll  
> announce here after the weekend. One thing I'm pretty sure of is that  
> we need a new name; I suggest we use "relation". ("relationship" or  
> "group" would also be ok for me, I don't really mind.) -

The terms 'Relation ', 'Relationship', 'Relation constraint' or even 'Dependency' are fine with me.

Why not take the shortest of those: 'Relation'

> I would like to enlist your help for the following areas of this sub- 
> project:
> 
> (a) Is there anyone who is good enough at hacking one of our existig  
> renderers - Mapnik, Osmarender, or the Postscript rendere

If we could make renderers capable displaying 'turn restriction' relationships or 'turn allowance' relationships 
on the slippy map it would be excellent for map proofreading on turn restrictions. 

'Turn restrictions' could become represented using an arrow pointing from way 1 to way 2 combined with an oneway street entry forbidden sign. 

> actually modify one of them to support one or the other kind of  
> relationship, a "superway" perhaps?
Is this not just a 'same name' or 'same object' relationship. Technically it is hard to prohibit that someone combines a highway and a river to a common 'superway'? 
 
> (c) The idea also needs "political" support. At some point in the not  
> so distant future, someone has to actually deploy the stuff on our  
> database server, and this is only going to happen if the powers that  
> be agree. As most of you know I'm only a very occasional visitor on  
> our IRC channel so I cannot argue for relationship support there.  I  
> hope that those of you who like the idea will do their part to  
> overcome skepticism.


Full support from my side. Here a definition of the relation API prototype for discussion:

http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.5#Create_new_relationship

I tried to keep as close as possible to your example.

Michael