[Talk-us] directions of ways in MassGIS data

Zeke Farwell ezekielf at gmail.com
Mon Feb 2 19:56:39 GMT 2009


It makes sense to me to reserve the Motorway classification for roads that
are consistently divided with limited access, and grade separated
interchanges.  It also makes sense to me to reserve the Primary
classification for roads that are not limited access, have same grade
intersections (stop lights, jug handles, slip ramps, but no interchanges),
and at the maximum are only divided my a raised median.   I also think it
makes sense to keep the classification of a road the same for as long a
distance as possible.  It makes for confusing maps when the status keeps
changing back and forth.

I use the Trunk classification for roads that do not fit cleanly into either
the Motorway or Primary classification.  These would be divided highways
that have both grade separated interchanges and same grade intersections.
Also roads that go back and forth between divided and non-divided.  The last
thing I use Trunk for is roads that have all the qualifications for a
Motorway, but only for a short distance, and that don't connect to any other
Motorways.  The only reason I don't use Motorway here is that it seems
stupid to have a small section of Motorway all by itself.  Others may

Two examples of where I have used Trunk are US 4 and US 7 near Rutland, VT:

Route 7 south of Rutland is sometimes divided, sometimes not.  It has
interchanges, but they are all same grade.  It also has regular
intersections.  It has characteristics of Primary and Motorway, so I
classified it as Trunk.

Route 4 west of Rutland is completely divided, two lanes each way, it has
limited access, and all of it's interchanges are grade separated.  It fits
the description of a Motorway, but on either end it degrades to a Primary
road, and it doesn't connect to any other Motorways.  Because it doesn't
connect to the greater Motorway network, I classified it as Trunk.

What do you think?  Does it make sense to classify all of Route 2 as Trunk,
or does it make more sense to classify it as Primary in some places and
Motorway in others?

Zeke Farwell
Burlington, VT

On Sun, Feb 1, 2009 at 10:33 AM, Greg Troxel <gdt at ir.bbn.com> wrote:

> In Massachusetts osm has state GIS data, and a number of the 1-way ways
> are the wrong direction.  This is particularly obvious for divided
> highways, e.g. Rt 2 inside 128, 495 near Rt 2.
> Clearly I could go edit these manually.  But I wonder if there is
> automated way to fix this, perhaps by going back to the massgis data
> (surely massgis would encode direction), spiffing up the import script
> and applying diffs.  Did this issue arise with TIGER data, or in other
> states with state-level data?
> Also, some of the classifications seem not quite right.  Rt. 2 is
> sometimes labeled primary, which is correct some of the time, but the
> length between Alewife and 128 seems to be to me a motorway.  Is it the
> general consensus that state and US highways that are divided and have
> only on/off ramps and speed limits of 55/65 be tagged as motorways?
> That's how I interpret the tagging guidance but wanted to ask before
> changing it.
>    Greg
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