[OSM-talk] Superways again

matthew-osm at newtoncomputing.co.uk matthew-osm at newtoncomputing.co.uk
Fri Mar 16 17:28:37 GMT 2007


On Fri, Mar 16, 2007 at 04:31:59PM -0000, David Earl wrote:
> talked about it in passing in Oxford a couple of weeks ago. I think making
> this change this would be unproductive.
> However, the concept of adding a higher level structure on top of ways is, I
> think, still desirable; at the same time requiring that Ways are what we
> all, I think, now believe they should be and do conventionally, i.e.
> contiguous, ordered, unidirectional, non-branching sets of segments.

I suggested to the list a while ago the following plan that would not require
all editors to be immediately updated. The idea is to extend segments to be
paths. This means that an existing editor will not break until a segment with >2
nodes is downloaded. A way then becomes the "superway" or "group".


  Node stays as node
  Segment becomes an ordered list of two or more nodes
  Way stays as an unordered collection of segments (now paths).

Then, push data from ways back down on to the "segments" again. This can be
automated (in fact, I've just written a ruby script that pretty much does that -
ways are fairly useless in their current form of not being paths, so it pushes
the data to the segments and then builds paths up from them).

I think this is the simplest method of updating, without breaking lots of
existing stuff.

> There are then lots of advantages to grouping such ways.


> Not much new in this message, but I want to light the match again.

Totally agree. I also appreciate that it is not an easy thing to be done
quickly, so accept that it may take a while to actually happen.



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