[OSM-talk] Divided roads proposal

Anthony osm at inbox.org
Thu Dec 3 16:14:40 GMT 2009


On Thu, Dec 3, 2009 at 10:58 AM, Steve Bennett <stevagewp at gmail.com> wrote:
> On Fri, Dec 4, 2009 at 2:40 AM, Anthony <osm at inbox.org> wrote:
>> 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
>
> What do you find kludgy about it? I thought it was quite elegant? It
> makes the division a property of the road, and lends itself to
> assisting with routing.

It doesn't seem to be general enough, but instead as an incomplete
lump of special cases.

>>to justify going through the database and
>> merging ways which were separated to represent roads with traffic
>> islands.
>
> I don't think anyone was proposing doing that. I mean, one *could* but
> I don't see what the compulsion would be.

So routers are going to have to handle two completely different ways
of doing the same thing?

>
>>  And doing so will likely lose data - specifically, the size
>> of the divider (which varies often enough to make divider:width=* an
>> insufficient solution).
>
> Well, a couple of comments there:
> 1) Do you think the divider widths as currently recorded are
> particularly accurate?

The ones I've done are.

> 2) Do you think it's important?

Not of huge importance, but I think it's something important enough
that it should eventually be recorded.

> 3) Do you think in a situation where we had accurate information about
> a non-uniform-width divided road, we would even consider throwing out
> that information and replacing it with this? Of course not.

See above regarding mapping the same thing two different ways.

> The point is, certainly in the areas I'm working in, there are lots of
> back streets with median strips that are sketched out fairly quickly,
> and there's nothing particularly interesting or important about the
> width of that strip, and using two separate ways to indicate the lanes
> on either side - *that's* the kludge. It's implying a higher level of
> accuracy and detail than we have.

I guess I'm spoiled with access to Yahoo aerials.  Still, if there's
nothing interesting about the median, why bother mapping it in the
first place?  You can still add the turn restrictions, which is the
important part.

>> 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.
>
> Yeah...but before that happens, the interface for editing relations
> has to be really natural.

I don't see why it does.  In fact, I think you're putting the cart
before the horse.  Define the relation in the wiki, and the editors
will follow.




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