[Talk-us] Separate relations for each direction of US & State highways.

Paul Johnson baloo at ursamundi.org
Sun Jan 12 02:21:14 UTC 2014

On Sat, Jan 11, 2014 at 5:37 PM, Peter Davies <peter.davies at crc-corp.com>wrote:

> Paul,
> One of the things that Martijn and I agree needs to be possible is for
> routes to change directional posting part-way along. This commonly happens
> on beltways like that around Minneapolis St-Paul, that around Indie, and on
> AZ Loop 101 and 202 here in Metro Phoenix.

US 101 also has a fun section where it runs parallel to itself for a
substantial distance in Washington State signed North/South, with another
sizable distance running East/West (with the midpoint being roughly Port
Angeles).  More confusingly, the east north/south segment puts the I 5
interchange at the South terminus (even though as the route runs, it's the
northernmost terminus).

> For my part, I also feel we need to accommodate strange directional
> posting like N in one direction and E in the other, as you appear to
> describe on the Tulsa - Muskogee Turnpike.  This is easy on fully divided
> highways like the Turnpike, as each directional "way" has its own role,
> even if both directions are in a single relation as you've coded for your
> area.

I may have the directions flipped, and I definitely know signage is less
than consistent, but you get the idea; it's right-angle cardinal, but I'm
pretty sure I got it right (directions matching the overall direction of
travel when you're at the foot end of the direction you're going).  I'd go
check right now but I really don't have the time or the inclination to
spend $3.80 in toll, 3 gallons of gas and 2 or 3 hours in the car for a
night-time observation run to the next metro area and back right now...

> I was excited to hear about N one way and E the other, as I've argued that
> we need to handle this on single carriageway, bi-directional ways, using
> (say) role=north;east.  In this case north would be posted as OSM forward,
> and east as OSM backwards.  If the Muskogee Turnpike actually were a single
> carriageway it would probably be better to code the ways "role=east;north"
> with OSM forward running from Tulsa to Muskogee and to the south beyond,
> because this is the increasing milepoint direction (according to
> Wikipedia).  Martijn has shown how routes' ways can fairly quickly be
> reversed and made consistent in terms of OSM forward, and I've done some
> too (e.g., ID 21).  This can simplify directional role posting on long
> single carriageway roads.

I'm still not huge on the idea of using cardinal directions as roles on
ways in a relation.  I'd love to know what folks thoughts are on this
versus below.

> Of course the M-TWP is not a single carriageway, so OSM forward actually
> runs in both directions, one on each carriageway, and the posting is simply
> "role=east" or "role=north."  But single carriageway "semi-motorways" and
> toll roads do exist, e.g., between Nara and Kyoto in Japan, or though the
> Japan Alps near Shirakawago, or around Interlaken in Switzerland, or
> through the Mont Blanc Tunnel between France and Italy. I've been lucky
> enough to drive each of these in the past three months in the course of my
> work, while thinking hard about OSM data structures.

Just so we're clear, we're talking about child relations having the role
east and north, right?  The way I see dual carriageways are with three
relations (though I'm increasingly seeing the value of doing something
extremely similar for route relations that aren't exclusively dual
carriageway for the sake of obviating the situation for navigation
engines).  I may switch to this in the future and convert existing
relations in Oklahoma if we can find a way to negotiate this hot mess we're
dealing with now (especially given the number of surface expressways that
turn into a single-carriageway boulevard within city limits, only to revert
back to an expressway on the other side of town, which I've been tagging as
primary in city limits and trunk outside).

Relation 1:
name=Muskogee Turnpike
operator=Oklahoma Turnpike Authority

north = Relation 2
east = Relation 3

Relation 2:
name=Muskogee Turnpike
operator=Oklahoma Turnpike Authority
all ways role=forward

Relation 3:
name=Muskogee Turnpike
operator=Oklahoma Turnpike Authority
all ways role=forward

> With this in mind I have coded three OK relations, one modified from yours
> for M-TWP northern section, one for the "free TWP" section posted as OK 165
> (also modified from your work?)  and a new one for M-TWP southern section
> (where no relation seemed to exist).  I've set them up with increasing
> milepoint "ways" first, and reducing milepoint travel second.

Works for me.

> You will find the directional roles as I think they are actually posted on
> the ground.  JOSM confirms that the ways are now in sequence in the three
> relations, using its little wiggly line in the relation analyzer.  There is
> one break only in each relation, where we switch from one carriageway to
> the other.

Try OK 165 now.  I just retagged it with my proposal.

> After a little legitimate research on Google's Streetview (not copying,
> but simply studying, as all good students should), so I concluded that the
> northern M-TWP section is not posted counter-intuitively, as I thought
> you'd indicated, but simply changes direction part way along.  You may know
> better, and should of course improve on what I've guessed.  My evidence is
> that the M-TWP on-ramp to Tulsa is posted "West" (not "North") on westbound
> E Harris Road. So I assume it switches at that point from N-S posting to
> E-W posting.  On eastbound E Harris Road I see the :"free" TWP on-ramp
> posted as "South". This direction switch is what we might have guessed from
> the road's alignment.
> But what say you?  Is the west/north posting truly inconsistent on M-TWP?

First, I'd like to propose for the sake of clarity, using postal
abbreviations are a must; TWP is throwing my brain a little.  ;o)  Tpk
is what signage and the postal service use for turnpikes most commonly.

As an aside, anyone paying attention to OSM Notes (I *strongly* encourage
folks to participate in this system, as well as the GeoChat system)
probably has noticed that I zealously annotate as I go (and probably to the
chagrin of the folks camping in #osm-us).  I do this in an effort to
encourage participation by sharing my knowledge when I'm not in a position
to take action on it at that moment, and often use shorthand that I'm
willing to explain quite a bit if it doesn't make sense by context with
available GPX, aerials, existing map data or local knowledge.  I really
wish OsmAnd+'s Notes plugin had a keyer system similar to OSM Tracker to
simplify the bug reporting process, and make it possible to single-touch
bug reporting using the current location to simplify entering a more cogent
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