[OSM-newbies] Joining two pieces of a way

[Per Lindström]

söndag 20 december 2009 22.37.06 skrev  Jeff Barlow:
> Per Lindström <per.lindstrom68 at gmail.com>  wrote:
> >söndag 20 december 2009 18.41.59 skrev  Jeff Barlow:
> >> ...What is a "turn restriction"?
> >
> >I tells you how you may continue in an intersection. In this case you are
> > not allowed to turn at all. Important information for routing software.
> >
> >> How is it rendered differently from a typical
> >> intersection?
> >
> >It isn't. At least not in Mapnik or Osmarender as far as I have seen.
> 
> Okay, all that makes sense. I'm still confused though. Where is
> this "turn restriction" information located and how can I view
> it? I found no indication of it by following the posted link.

There may be other sites that use the OpenStreetMap data to show this kind of 
information on a map, but at least I have'nt found any.
The only way I've found to fins this information is in the editor. I'm using 
Potlatch that can be found by pressing "Edit". "Edit with save" is safer than 
live editing, so chose that. Click on a road segment leading to the 
intersection. You'll see a couple of relations. Relations look like tags but 
have white text on a slightly darker grey background. Two of them are called 
"restriction" and has 'roles' (thats the words "to" and "from" to the right of 
the word "restriction") on them. If you click on the word "restriction" you'll 
get more information about this restriction. It says that the type is 
restriction and that restriction is "only_straight_on". At least in this 
intersection every restriction relation has three members: "from", "via" and 
"to". You might have guessed that "from" is the road you are coming from, that 
"to" is the road you're going to and "via" is the intersection itself.
For more information see this page: 
http://wiki.openstreetmap.org/wiki/Relation:restriction
-- 
/Per Lindström