[OSM-talk] TAG-Suggestion: highway:trailer_shipment
Carsten Moeller
cmindividual at gmx.de
Sun Jan 17 11:14:11 GMT 2010
Felix Hartmann schrieb:
> I think the main part that has to be done here is that ferries, or
> motorails however as well aerialways get connected to the main road
> network using lines (routing over polygons is so complicated that no
> router will soon master it in a useful way).
>
> How they are connected should be dependant on the transport mode to use.
> Image huge ferries with different, but consistent places to enter.
>
> We could have
> highway=footway & pier=yes (or similar)for pedestrians entering the
> ferry (this is actually one of the rare cases I like to see footway and
> not path),
> highway=service & motorcycle=yes & foot=no & bicycle=yes
> highway=service & access=no & motorcar=yes & hgv=yes
>
> And the ferry route should connect all three.
>
> Another example would be a cable_car.
> We should have highway=footway (or another key) to connect the street
> network to the cable_car. If there are steps inside the building, well
> then lets add a section highway=steps......
>
>
> The principle should be no matter what kind of line there is that can be
> used somehow, it should be interconnected with all other transport
> usable lines. This means that we should also connect railways to roads,
> because otherwise no autorouter can calculate routes using busses and
> trains (with walking from one to another) for example. Only airports I
> would rather just connect by having a relation list to which other
> airports you can get from airport XY.
I get to the conclusion that we exactly have two perspectives. First
there is the question of how to get from A to B including public means
of transport. The other one guides me to the closest parking lot. A
cable car for instance has the same quality as an aerialway. But not as
highway=footway. The latter is rather like a highway=service. You can
use a car. Ok. it might be forbidden but you can. Offering mountain tops
and similar things as addresses on your routing topology will blow up
the data dramatically.
The key to a fast routing is the reduction of data. "Make things as
simple as possible, but not simpler" (Einstein). There are some grey
zones. I am living in a "highway=pedestrian" connected to a
"highway=service", so I decided to take these tags into account but gave
them a low priority so the router selects them only if there is no other
way.
I do agree. Railways, aerialway etc. should be connected to highways.
But this should not be expressed by connecting same nodes. Here ramps or
links come into play. If you have a closer look at todays OSM-Data
railways are in fact connected to streets. But I wonder if you'd like to
stop a train by parking your car on a railroad crossing ;-) What about
aerialways? Are they connected, too? In the air?
A highway=steps would imply you can use your car here. I think we should
strictly distinguish between highway and other tags. If I understood the
intention correctly then highway is something you can drive on. Even on
highway=pedestrian but not on steps.
I hope OSM will take these two perspectives into accoung one day. So we
can have routable highway tags like highway=railway, highway=ferry, etc.
These are much easier to handle (and to tag) than railway=rail +
motorcar=yes + amenity= ... and so on.
On the other hand we should consider the real world. This of course
means we'll need to build topologies on relations or tags like
motorcar=yes, railway=rail.
Regards
Carsten (alias PiMapper)
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