[OSM-talk] Divided roads proposal

[Anthony]

On Thu, Dec 3, 2009 at 4:06 AM, Steve Bennett <stevagewp at gmail.com> wrote:
> I find the current practice of duplicating minor roads when there is a
> median strip pretty unsatisfactory.

I was thinking about this recently when we had the "map everything as
areas" thread, and I have to agree with you to some extent (though not
completely).  Duplicating and separating makes more sense when the
roads are completely separate - separate entrance/exit ramps, etc.
For a road with a median strip, we're better off mapping the median
strip on top of the road.

I'm not sure how this would work without using areas, though.  And
even then, it'll be complicated.  I think the proposal at
http://wiki.openstreetmap.org/wiki/Proposed_features/Divided_road is
far too kludgy and temporary to justify going through the database and
merging ways which were separated to represent roads with traffic
islands.  And doing so will likely lose data - specifically, the size
of the divider (which varies often enough to make divider:width=* an
insufficient solution).

On Thu, Dec 3, 2009 at 5:17 AM, Richard Mann
<richard.mann.westoxford at googlemail.com> wrote:
> On Thu, Dec 3, 2009 at 9:39 AM, John Smith <deltafoxtrot256 at gmail.com>
> wrote:
>>
>> 2009/12/3 Steve Bennett <stevagewp at gmail.com>:
>> > I find the current practice of duplicating minor roads when there is a
>> > median strip pretty unsatisfactory. Even disregarding the effort, the
>> > end result never renders well: usually the street name is written
>> > twice, the one-way arrows get messy etc.
>>
>> That's a problem with the rendering, not with the mapping.
>
> Unless you want to write routines for pre-processing two almost-parallel
> ways back into a single way so it can be rendered neatly, I suggest it's a
> mapping problem. Don't make work for other people if you don't have to.

The thing is, you kind of have to.  There has never been a one-to-one
correspondence between "roads" and "ways".  It's not just dual
carriageways that sometimes get rendered poorly, it happens when ways
are split as well.

Mappers could assist the renderers by creating relations, so every
single way which is part of Dale Mabry Highway (as in
http://en.wikipedia.org/wiki/Dale_Mabry_Highway) gets put into a
single relation.  I think that's more the way to go.  Solves lots of
problems in addition to that one.