[Tagging] Mapping nonexistent paths
pelderson at gmail.com
Tue Mar 23 11:57:07 UTC 2021
I tag lots of recreational routes as route relations. A route is a
continuous chain of connected ways. In lots of places I need a linking way
to keep the chain continuous, especially in hiking routes, because there
is no actual official link or path.
E.g. Often a cycleway is present for a stretch along a road. Then it just
stops. Pedestrians and cyclists will continue on the side of the road. If
the path is mapped, it will connect, at the end, to the centerline of the
road with a virtual path, to provide a continuous chain for
routing (including "manual routing" in route relations). This gets more
complicated when footways and cycleways are both mapped separately, which
is an increasing trend.
You could say it's tagging for the router, but it's standing practice to
map for continuity. As soon as routers and the standard OSM track export
can be reasonably expected to deal with non-continuous routes and route
relations, i.e. finding a solution for missing links which adequately deals
with trajectory, access and other characteristics of the terrain where a
connection is needed, I am all for mapping just what there is. As it
stands, I think we need to specify where a route is ok and where not, and
that is achieved by mapping the links so you can add properties needed for
chaining and routing.
How exactly to tag the linking ways is verse 2.
I particularly like the highway=path, path=link and highway=footway,
footway=link and highway=cycleway, cycleway=link idea. It is very
intuitive, stating exactly what is mapped, and it does not depend on any
particular physical characteristic. It's still verifyable by looking at
what most people do on the spot. E.g. a pedestrian will cross a pedestrian
area from entrance to exit, or step over a kerb or a grass strip onto the
cycleway or road, even step over a ditch, climb a hill with trees, cross an
area of sand dunes to the path at the other side. Humans can do that
without help, but currently we still have to help the software.
Op di 23 mrt. 2021 om 11:37 schreef Bert -Araali- Van Opstal <
bert.araali.afritastic at gmail.com>:
> I am sorry but I am still not seeing the advantage or added value to
> introduce keys or values to indicate that something is "less visible" or
> "less verifiable" or virtual or whatever you call it. I can't fit it in the
> model that exists in my mind how we map things, especially ways in OSM.
> All highways, all their connections, all rivers are virtual in OSM, all
> routes are virtual. We map them by drawing and connecting ways across
> surfaces. A pavement that stops "early" doesn't mean the path, the route
> people walk stops there. That is insufficient completeness in the mapping.
> Every highway or lane is mapped with a "virtual" line in the middle, the
> "virtual" route people or vehicles follow across a surface, be it asphalt
> grass or whatever.
> Ferries and boats move across a lake on "virtual" routes, they just follow
> a path on the water surface, in many cases not aligned by buoys or other
> The same for coastlines, the "virtual" coastline is where the median is
> between the salt and fresh water. In cartography many times just a
> straight line. You want to indicate the river connects to the water body
> and which route boats or ships follow, you map it, with our present
> complete "virtual" waterway schemes.
> I still have to see the first example where that doesn't apply or is not
> described nicely in our wiki.
> What does adding an additional tag add to this concept ? Makes it more
> complex to the mapper, because he has to add a tag for something considered
> more virtual in an already virtual scheme ? What is the added value for the
> mapper, I see none.
> What is the added value for the router ? I can't imagine even one? Do
> you think routers will evaluate the virtual tag, no they just look at the
> ways, the routes in general that are already there. Knowing that it is
> perceived as more virtual by some has no added value for the router.
> For the renderer, other data users ? Any added value for a virtual or
> invisible tag in comparison with what we already have ? I can't find any.
> Please show me an example where the current tagging would be considered
> less favourable to be used as is ?
> So, thank you for making this proposal, you made some nice examples which
> we could maybe add to the highway page. But it's just examples how OSM
> provides a bright and consistent way to map complex realities and
> behaviour, AS IS. It works, use it as intended, don't make it more complex
> by adding tags without added value.
> Bert Araali
> On 23/03/2021 12:38, Martin Koppenhoefer wrote:
> sent from a phone
> On 23 Mar 2021, at 10:23, Niels Elgaard Larsen <elgaard at agol.dk> <elgaard at agol.dk> wrote:
> Can anyone give an example of such a sophisticated router available to OSM users?
> the routers don’t have to be sophisticated if you connect highways to polygon highways, it’s sufficient for most cases to route around the borders (will be a little bit longer, but mostly not have practical consequences for the suggested route)
> Cheers Martin
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