[OSM-newbies] tertiary dirt roads?

Paul Johnson baloo at ursamundi.org
Wed Nov 25 05:49:47 GMT 2009


James Ewen wrote:

> Okay, so above, you would consider a forest service road as tertiary.

A forest service /highway/ as tertiary.  These have two-digit forest
service road numbers.  The vast majority of forest service roads have
two or three digit references, and are certainly tracks (these were all
incorrectly imported by TIGER...)

> Here's a link to a road through the bush near Salem, Or.
> http://tinyurl.com/yjh7xgw
>
> This is a paved 2 lane road. If you were to double the width of this
> road, straighten it out,  and change the surface to gravel, you'd have
> something similar to what I am talking about.

That one would be tertiary under the county system.  This would be a
well known (to Boy Scouts at least...) tertiary in the Forest Service
system (Dufur Mill Road aka Camp Baldwin Highway at Brooks Meadow Road,
just a few minutes from Camp Baldwin).

http://bit.ly/8ld2v8

> Here's a link to a smaller road that takes you from the government
> road grid up to the top of Whitecourt Mountain where there's a
> forestry lookout tower, and also a bunch of radio towers.
> http://tinyurl.com/y9notsa

I'm not entirely sure priority is correct on those.  If someone can
donate me a Kia Sportage, Suzuki Sidekick/Samurai or similar light 4x4,
I'll be happy to go take a closer look.  These appear even by name to be
of such minor status as to not even warrant a name or a reference,
instead called by what range and township it lines up on relative to the
Willamette Meridian (for those who aren't familiar with surveying in the
western US, please see
http://en.wikipedia.org/wiki/Public_Land_Survey_System).

> Here's a link to a paved road in the bush in Oregon.
> http://tinyurl.com/yhpd4xw

That's a county road, probably should be tertiary based on what I'm
seeing from that link.

> Both are at the same zoom level. The smaller road in Alberta is larger
> and easier to see from the air than the one in Oregon.
>
> Here's the Oregon area in OSM...
> http://www.openstreetmap.org/?lat=45.156&lon=-123.5106&zoom=15
>
> SW Gilbert Creek Road is tagged as a track... a paved striped roadway!

Not sure what's going on there but that also appears to be a county road
(tertiary).

> Try planning your route between Salem and Corvalis but you'll have to
> do it at zoom level 14 on OSM, and pretend that all the roads are
> residential, where they are all white, including the primary highways,
> and motorways. How long would it take you to figure out the route to
> take between the two cities?

10 seconds, Corvallis is the closest major city to Salem so you can
usually pick up on it from the trailblazers.  Purely by the map is
another matter; I haven't been out southwest of Salem in ages.

> Would you be able to pick the fastest and
> best quality roads?

The trailblazers follow tertiary or better roads.

There's a lot of things about the map heading out towards Corvallis that
is plain wrong, largely as a result of unverified TIGER imports.  It's
not clear to me if anybody is actively mapping out that direction.






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