Re: [Tagging] Delete not marked walking routes?

[Friedrich Volkmann]

On 20.09.2015 08:45, Pee Wee wrote:
> What do you think?
> 
> Is is OK to have (walking) routes in OSM that have no visible marks on the
> ground and if so under what conditions?

First of all, we need to distinguish ways and relations. A path may be
visible or invisible, and a route may be actually marked/signposted or not.
So there are 4 possible combinations. You certainly mean relations for
unmarked routes consisting of visible paths, but let's have a look at the
opposite combination first: A relation for a marked trail with some section
where no path is visible (e.g. crossing a meadow). If we map only what is
"verifyable on the ground", as was suggested in some answers, we must not
map invisible paths. So we'd end up with incomplete relations that are hardy
routable, and whose statistics (length, heigth profile, % paved, etc.) are
incorrect. That's why most mappers do map those route segments even though
they are not verifyable on the ground. But hang on - are they really not
verifyable? There's a marked trail going off one end of the meadow, and a
marked trail going off the other side of the meadow. So we do see that the
route crosses the meadow. We do not see the invisible path, but we see that
there *is* an invisible path. It is verifyable or not, depending on how we
think about it.

I recently mapped a climbing route that is invisible from start to end. But
is has been documented in climbing guides for decades. I was able to
identify the rocks, ravines etc. described in the books. So the route is
verifyable on the ground - but only in conjunction with the climbing guides.
If all of these get lost in a fire, the verifyability will also be gone. But
hey, that's the same for the names of peaks, ridges, valleys etc. There's no
sign "Mount Everest" on the peak of the Mount Everest. The peak is
verifyable on the ground, its name is not. We map the names because they are
common knowledge. The climbing route I mapped has been common knowledge as well.

A hiking route suggested in one single book by one single author can hardly
be considered common knowledge, especially if the the route is just a
combination of paths that were already known before. That kind of routes do
not belong in OSM.

I should also mention that I did not create a relation for the climbing
route mentioned above. I just mapped the highway=path. Why would we need a
relation if the route is not marked, and all the other tags can be set on
the ways directly? Looking at the relations I found via your first link
(rel-id 2099391, 4108560), I wonder what tags are supposed to justify a
relation. What do ref=*, name=*, colour=* etc. mean when the route is
neither marked nor signposted in situ? Is ref=4b the page number in the
book? Is name=PP_5 the chapter in the book? Is colour=aqua the colour in the
book? What about isbn=978-2-930488-18-9? A route cannot have an ISBN. So
that's obviously the ISBN of the book. This is cleary a misuse of OSM. OSM
is a database for geographic data, not a book index. These relations need to
be removed, there's nothing to discuss about that.

-- 
Friedrich K. Volkmann   http://www.volki.at/
Adr.: Davidgasse 76-80/14/10, 1100 Wien, Austria

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Re: [Tagging] Delete not marked walking routes?

[Mateusz Konieczny]

On Tue, 22 Sep 2015 18:59:24 +0200
Volker Schmidt  wrote:

> In addition a cycle route that has been proposed and is likely to be
> implemented within he next few years can be inserted in OSM as a cycle
> route relation with the additional tag state=proposed.

I would strongly oppose adding merely proposed routes, especially in
way that would be likely to be interpreted as a real route by data
consumers (it would cause problems described in
http://www.openstreetmap.org/user/Mateusz%20Konieczny/diary/35702 )

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Re: [Tagging] Delete not marked walking routes?

[Volker Schmidt]

I would strongly suggest to stick to an approach for hiking routes that is
similar to the one commonly applied to cycle routes:
"Cycle routes or bicycle route are named or numbered or otherwise signed
routes." ("cycle routes" wiki page)
In addition a cycle route that has been proposed and is likely to be
implemented within he next few years can be inserted in OSM as a cycle
route relation with the additional tag state=proposed.
Routes that are not trail-blazed in some way and are not proposed by some
kind of official body should not be mapped as cycle route relations.

Volker
Italy
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[Tagging] Feature Proposal - Voting - (nutrition_supplements)

[Alberto Chung]

Hi again! Voting process is still opened for nutrition_supplements (6 days
remaining)

amm... somebody knows if i can add a proposed icon yet? if not, how i
should do that?
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Re: [Tagging] Delete not marked walking routes?

[Lauri Kytömaa]

Frederik Ramm wrote:
> Our general rule is that things we map must be verifiable on the ground,
> i.e. someone who goes there must be able to check that the feature does
> indeed exist as described in OSM.

This message isn't really contradicting what you wrote later in the
message, but I have to remind others that verifiability doesn't need
to be easy, or it might not even be possible without expert knowledge,
equipment or reference to "other" material not directly present in the
location being mapped.

As a counterexample, let's consider an underground water or heat
pipeline in the city; these are constantly being repaired, improved
or preemptively replaced. A mapper sees the open repair pit on a road,
interpolates the pipeline's location and turns with other known features
and imagery getting the accuracy down to, say, 50 cm. A month later,
the next mapper would only see the patched pavement, and possibly
some manhole covers far or very far apart; only the general alignment
can be inferred. Then, a year later the whole street is repaved, and
only the manhole covers remain, but one couldn't know (for some level
of certainly) whether they belong to pipelines crossing the street, or
whether one pipeline runs along the street, unless one surveys the
whole neighbourhood. Nobody is however suggesting the pipeline
should be removed, or turned into a straight line just because every
casual mapper can't verify the form and attributes on site.

In fact, even administrative boundaries can be verified "in place",
in theory, but it would normally take a whole lot of time and incur
expenses: build an illegal shack anywhere near the border, and wait
for the officials to react, and read the papers you get to see which
area you were in. And that could be costly. Likewise, national borders
can be verified by doing something that attracts the interest of the
enforcement authorities (police, border guard, military); when you see
which country they serve, you know which country you were in. That's
hardly "not present" on the ground.

> "official" bike routes
>...
> (if not fully
> signposted) by a national body, they were ok to have in OSM. They
> wouldn't always be verifiable on the ground but it would be easy and
> straightforward enough for anyone to verify them using existing material.

Back on the topic of this thread, the unmarked but published routes,
I would be on the inclusive side, (roughly drafting) "as long as the exact
route is or has been used for the same purpose by several parties (n>>2)
on different dates, and is not the only connection between two destinations"
or something like that. This would rule out the personal dog walking routes,
single mapping walks and other personal notes of the type "I was there",
but would "allow" the routes of e.g. marathon competitions, long distance
cycling races and routes of motorcar races on the public road network, when
the event is not a one-off. The routes are very visible for some time each time
the event is held; either a line on the ground, fences or other barriers, or
just signposts that get removed later. If we record the data, it _could_ be
reconstructed in the future even if the relation is later destroyed and
eventually deleted, if we don't, it's soon gone forever. The last part
of the draft
sentence above is to say that when a single forest trail connects two villages,
it's probably not a route in the sense of this discussion, but when two or
more trails connectthe same villages but the overwhelming majority of
pedestrians going from A to B use only one of those trails (for whatever
reason), it 'could' be something in the DB; not part of a walking route
network or anything, but not something that should be deleted straight away,
either. If there's a signpost for it at the ends of the route, that's
even better.

-- 
alv

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