[josm-dev] self-intersecting ways

[Paul Johnson]

On Mon, 22 Mar 2010 01:50:23 -0400, Anthony wrote:

> On Mon, Mar 22, 2010 at 12:35 AM, Paul Johnson
> <baloo at ursamundi.org> wrote:
> 
>> On Sun, 21 Mar 2010 20:09:43 -0400, Anthony wrote:
>>
>> > When I lived in New Jersey it was the same way, and I'd imagine it's
>> > the same way in most of the United States.
>>
>> I'd say more research is needed before we call that conclusive.
> 
> 
> I guess.  I'd love to hear of a statewide counterexample.  If the
> right-of-way doesn't extend beyond the road, where are you supposed to
> walk?  (I know of some local situations where there is no walking space
> on the side of the road, but not of any entire states where this isn't
> the norm.)

At least around Portland (and probably statewide since I don't have any 
reason to believe this isn't the case elsewhere, but I don't have any 
high-quality WMS property maps and aerial photography to compare to), the 
property lines for the right of way extend beyond the roadway to include 
space for future expansion and sidewalks (or in cases where cyclists or 
trucks aren't allowed on the main route, a third carriageway for 
cyclists, such as I205 through East Portland or I5 near Terwilliger).

> That's a different question, though.  In OSM, the way which is tagged
> highway represents the physical road, right?

Centerlines, actually.

> I assume this is the case
> because we tag dual carriageways as two ways, as there are two
> physically separate roadways, whereas there is generally only a single
> right of way. Outside of dual carriageways I guess it's ambiguous,
> unless there's a width tag, in which case, what is it that we're
> supposed to measure the width of?

This is where an area tagged landuse=highway or landuse=railway would 
make more sense, since the width of the right of way is frequently 
variable, particularly along dual-, triple- and quadruple- and quintuple-
carriageway¹ roads.

> I can think of at least three different possibilities - the paved 
> surface, the actual lanes used for traffic, and the entire right of way 
> including the unpaved shoulder
> and/or the sidewalks and/or the [
> http://en.wikipedia.org/wiki/Tree_lawn].  Which would you say is
> correct?

Centerlines as the linear way, landuse incorporating the entire right of 
way.  We currently handle rivers somewhat similarly.


¹ I know of at least one quintuple-carriageway:  I205 in East Portland 
has several segments where there's a seperate carriageway for bicycles, 
and then four carriageways for a freeway in a local/express 
configuration.  http://osm.org/go/WIDne7cb