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#1 2017-05-02 13:36:12

karussell
Member
Registered: 2012-07-26
Posts: 85

ferry, ford and barrier default access values

What are the default access values that should be assumed for a ferry, a ford and a barrier when it comes to a routing engine? This is often asked on our forum and we use very conservative defaults i.e. do not allow to pass a gate or fords. E.g. fords can be potentially dangerous and gates could be closed and not accessible by car or truck. When discussing this for a specific OSM note I get friendly responses like:

A gate that have no restrictions should be passable just fine unless the router used is stupid.

I can find the default access values for 'highway' here, even per country: https://wiki.openstreetmap.org/wiki/OSM … strictions but cannot find an 'official' way of how to interpret this for ferry, ford and barrier. What to do here?


graphhopper.com route planning web services based on open source and open data

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#2 2017-05-02 14:08:19

Gazer75
Member
Registered: 2015-03-19
Posts: 5

Re: ferry, ford and barrier default access values

If mappers can't be bothered to add access tags then just ignore the barrier IMO. It would encourage proper access tagging, and provide a failsafe for barriers that were just added without thinking about access tags.

For ferries, as long as the route is connected directly to a road that can be used by motor vehicles then just accept all modes of transportation. Ferries that are for passengers only should preferably be connected to the road network using a footway/path.
You can also use the ferry=trunk/primary/secondary/... tag to see if it is part of the regular road network and thus can be used by motor vehicles.

For the small combo ferries in Norway it is best to just connect the route via footway at the docks where they do not accept motor vehicles.

It is impossible for a router to cover all "what ifs".

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#3 2017-05-02 14:15:25

TZorn
Member
From: Leverkusen
Registered: 2015-06-02
Posts: 269

Re: ferry, ford and barrier default access values

According to the barriers wiki page you are right to assume an access=no: "Barriers with undocumented default access imply access=no."

However there are rarely any defaults documented. I am not aware of an overview but defaults may be found in the single barriers' wiki pages, like the one for barrier=bollard where they are listed in the implies section in the info box. I guess for now every data consumer needs to fill the gaps by their best judgement. Ideally, we would start a discussion on the defaults.

Since I have come upon this sad situation I have started to put explicit access tags to every barrier I map.

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#4 2017-05-02 14:22:08

karussell
Member
Registered: 2012-07-26
Posts: 85

Re: ferry, ford and barrier default access values

For ferries, as long as the route is connected directly to a road that can be used by motor vehicles then just accept all modes of transportation. Ferries that are for passengers only should preferably be connected to the road network using a footway/path.

Thanks, this is a simple&good idea to improve the defaults in a relative safe manner.

I am not aware of an overview but defaults may be found in the single barriers' wiki pages

Yeah, we try to consider these and an overview would indeed improve the situation.


graphhopper.com route planning web services based on open source and open data

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#5 2017-05-02 15:02:12

hadw
Member
Registered: 2014-09-02
Posts: 593

Re: ferry, ford and barrier default access values

I would say a ford was the same as a ferry.

In particular, access restrictions do not represent judgements as to whether it is sensible to use a feature, only whether it is allowed.  Fords may not be completely clear-cut, because their existence is more a matter of practicality than law.  Your router may have a policy not to route over fords, but that should be applied equally to ones with access explicitly set to yes.  I think you would need to go up to designated before you should consider assuming it was the safest option.

Ideally, if the ford is hazardous, the strength of the current (not sure how you tag this) and the depth of the water should be used to make that judgement, in the router.

(This often seems to come up for bicycle routes.  People want to put cycle=no, because they think cycling is dangerous, when cycling is perfectly legal on the highway in question.)

I would also generally assume that gates have the same access as the most restrictive of the highways on either side of them. My gut feeling is that gates are under-mapped, at the best of times.

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#6 2017-05-02 17:16:23

SomeoneElse
Member
Registered: 2010-10-13
Posts: 662

Re: ferry, ford and barrier default access values

TZorn wrote:

However there are rarely any defaults documented

In some cases (e.g. barrier=gate) it makes absolutely no sense to have a default - some gates are private, some public.  As has already been suggested, the best approach is surely to look at the access rules on the ways connected by the barrier.

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#7 2017-05-03 07:58:01

TZorn
Member
From: Leverkusen
Registered: 2015-06-02
Posts: 269

Re: ferry, ford and barrier default access values

SomeoneElse wrote:

In some cases (e.g. barrier=gate) it makes absolutely no sense to have a default - some gates are private, some public.  As has already been suggested, the best approach is surely to look at the access rules on the ways connected by the barrier.

True. So it's very questionable if a access=no should be implied at all as default for all barriers.

On the other hand there are plenty of barriers (bollards, blocks, ...) where the access restrictions on either side of the barrier are unlimited, just the passage through the barrier is restricted to certain transport modes.

Last edited by TZorn (2017-05-03 16:06:23)

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#8 2017-05-03 09:45:06

escada
Moderator
Registered: 2011-08-13
Posts: 1,177

Re: ferry, ford and barrier default access values

SomeoneElse wrote:
TZorn wrote:

However there are rarely any defaults documented

In some cases (e.g. barrier=gate) it makes absolutely no sense to have a default - some gates are private, some public.  As has already been suggested, the best approach is surely to look at the access rules on the ways connected by the barrier.


Unfortunately, this does not work for bollard in the middle of a street, used to forbid through traffic of cars. Cars can drive from both side up the bollard, but cannot pass.

According to https://wiki.openstreetmap.org/wiki/Barriers , each barrier should have its own default values, defined on the wiki. In case they are missing, access=no should be assumed.

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#9 2017-05-03 10:16:14

SomeoneElse
Member
Registered: 2010-10-13
Posts: 662

Re: ferry, ford and barrier default access values

escada wrote:

According to https://wiki.openstreetmap.org/wiki/Barriers , each barrier should have its own default values, defined on the wiki. In case they are missing, access=no should be assumed.

I can understand why a router might want to consider a "truly unknown" barrier type as "access=no", but a gate is hardly an unknown barrier type; it's just one for which no default value makes sense.  Wiki editors sometimes write things that make sense for the small subset of the items that they're familiar with, but they often forget that OSM is a global project and customary access varies hugely by region (just within the UK there are 3 different sets of rules).

Also, actually looking at barrier types in use really isn't that difficult.  I did it from a rendering perspective a while back (the results are at https://github.com/SomeoneElseOSM/Someo … .lua#L1015 ) and it didn't take more than a couple of hours in total, which included asking some people what sort of barrier an XYZ actually was.

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#10 2017-09-25 07:43:14

boldtrn
Member
Registered: 2016-05-24
Posts: 7
Website

Re: ferry, ford and barrier default access values

I just wrote an overpass query that returns gates that are placed on major highways and has no access tag. Maybe this helps in adding access tags to these gates. I just added a couple of notes on OSM.


Kurviger a motorcycle route planner that favours curvy roads and slopes, also available as Android app

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#11 2017-09-25 13:27:18

Allroads
Member
Registered: 2011-03-05
Posts: 2,287

Re: ferry, ford and barrier default access values

A gate needs a new tag, there gates, that are mostly all the time open, drive through, without opening and closing method, only till the time the road is iced/closed.
Some routers give the gate a penalty and give a around route. access=yes, does not say anything about open/closing method.
Is https://wiki.openstreetmap.org/wiki/Key:drive_through a good key?

Bollards without good tagging is a problem for horse, mofa, moped and motorcycle.

For ferry, you can not give the advice, way in front, footway or path, both have defaults (path is very discussable, not motorized vehicle, there a lot of path to drive with for example a motorcycle, people forget to set it open for motorcycle etc.)(track is double_tracked, you have to choose track or path, single_tracked), but there are ferry's which you can use with mofa, moped, motorcycle. the single_tracked_motor_vehicle category. Access, it must be on the ferry line.

Most defaults give a turn on the working flow, a different system of tagging, forgetting to think about, which means, that it have a big effect other transportation modes, the little groups.

Treat, all modes equal Basic rule?


The JOSM default preset, give foot and bicycle as a check, all modes must be mentioned and ready to check. This give mistakes in tagging. For mofa, moped, etc. Also the default is already cooked in this default, often not usable, let the tagger make the decision.

Bottom line, defaults, have major impact in the quality of tagging and when not almost right (There are always little exceptions) , everywhere, it should be avoided.

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#12 2017-09-25 14:30:38

hadw
Member
Registered: 2014-09-02
Posts: 593

Re: ferry, ford and barrier default access values

The reality is that getting people to add access at all is difficult.  As side issue on a recent question, I noticed that a swimming pool and sports pitch within a gated community that had no access tag, and so would be treated as open to the public, and it is very common to see "public" car parks that are almost certainly private, but take significant effort to verify as such.

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#13 2017-09-26 01:27:21

boldtrn
Member
Registered: 2016-05-24
Posts: 7
Website

Re: ferry, ford and barrier default access values

Allroads wrote:

A gate needs a new tag, there gates, that are mostly all the time open, drive through, without opening and closing method, only till the time the road is iced/closed.
Some routers give the gate a penalty and give a around route. access=yes, does not say anything about open/closing method.
Is https://wiki.openstreetmap.org/wiki/Key:drive_through a good key?

Yes opening and closing of gates are an issue, but most accessible gates on major roads that I know are usually open anyway. I think some routing engines add a penalty of some minutes for each gate.

I don't think that drive_through would be a good match BTW, as described in the wiki, it is meant for drive throughs of restaurants or other amenities. If possible, I always vote for not mixing tags. Maybe having a new tag like open or is_open.

Bollards imply access=no, foot=yes, and bicycle=yes. Usually, bollards are added to avoid people shortcutting through a residential area at peak traffic and should therefore IMHO be avoided for motorcycle routing as well. Still locals will use it as a shortcut, but at least routers should not lead traffic there.

Regarding ferry defaults, yes every ferry should be tagged properly, but reality shows that ferries are mostly under tagged. For Kurviger, we had to add motorcycle access tags to a lot of ferries, as a lot of mappers don't consider motorcycles for ferry access, but a lot of ferries transport motorcycles. So I think having some assumptions, e.g., if ferry is connected with a major highway then it probably transports cars and motorcycles, maybe even trucks to some extend. A good example is the Elbfähre, which at several crossings had no motorcycle tags, but is connected to secondary highways on both sides.

hadw wrote:

The reality is that getting people to add access at all is difficult.

Very true, yes. Part of the issue is that you cannot differ between an accessible and not accessible gate on the map. So if one only cares about cartography, one might not care about the access of the gate.


Kurviger a motorcycle route planner that favours curvy roads and slopes, also available as Android app

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