[OSM-talk] dead-end roads

Lars Aronsson lars at aronsson.se
Tue Sep 19 11:29:32 BST 2006


Wollschaf wrote:

> The roads that do get wider to turn your car around are usually 
> not wide enough to justify modeling this using segments;
> 
> I just don't have any clue how to find a proper name...

In Swedish, this is called a "vändplan" or "vändplats", which 
literally translates to German wendeplan/wendeplatz, English 
turn-place. In reality they often have the asymmetrical shape of a 
mirrored P, where you drive in straight, turn left, and have 
enough room to turn around.  There is a special roadsign that 
prohibits parking in the "turning zone", 
http://images.google.com/images?q=v%C3%A4ndzon

And yes, the Swedish national road database (NVDB) uses a node 
attribute to indicate them, rather than line segments.  The end 
node is drawn like a circle a little wider than a normal line 
segment.  Example images are found in section 7.4.11 of their 
technical specification http://www.vv.se/filer/26505/vagnat.pdf

  Vägslut i vändplan

  Där en väg slutar i en vändplan eller annan större öppen yta, 
  placeras noden i skärningspunkten mellan referenslinjen och den 
  bortre kanten av den trafikerbara ytan.

My translation:

  Road ends in turn-place

  Where a road ends in a turn-place or another larger open area,
  the node is placed in the intersection of the reference line and 
  the far edge of the trafficable area.

  Road ends in a turn-loop

  Where a road ends in a turn-loop with a physical obstacle in the 
  center of the loop, a reference line shall depict the actual 
  location of the loop.

Here, a "reference line" is a sequence of line segments.


-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se




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