Hi, in the National Park Feldberg (Black Forest, Germany), in winter only certain paths are allowed for use by any means to protect wildlife if there is snow. This is announced via websites, information boards and leaflets, such as this one (in German). Paths through the cross-hatched areas are forbidden. Paths that are not permissible are often (not always) locally marked by corresponding signs. The signs are sometimes specific for a path, sometimes more general for an area. Yet, all routing ignores this and guides (snow shoe-)hikers through the protected areas. The organization could not provide GPS data for the blocked region (hatched in orange in the PDF). Is there a way to tag this in OSM, I couldn’t find a matching discussion in the forum?
From the way I read the conditional restrictions page on the wiki access:conditional=no @ snow might what you’ve described (usage here). The chances of routing software knowing there is snow is small, but it’s theoretically possible for them to ask the user.
If by “announced via the website” you mean that they have a closed winter time period with the website saying when this is in effect then access:conditional=no @ winter might be appropriate as is described for certain speed limits in Finland.
I had a look at the values for key access and filtered on snow and nothing comes up.
So nothing tagged yet, but Any tags you like.
Maybe better is to go for access=no (default) + access:conditional for when there is snow.
The leaflet and website do not specifically state that the restrictions apply only when there is snow, though the motivation is the increased effort for animals when there is snow. There is also no specific calendar window given.
@emvee : Shouldn’t it be
access=yes
access:conditional=no @ winter
Maybe you want to get in touch with @Feldberg-Ranger (Feldberg-Ranger | OpenStreetMap).
In general, this can be handled with Conditional restrictions - OpenStreetMap Wiki like Way: Sägebachschlag-Steig (149597317) | OpenStreetMap. If there is no explicit time-span available *:conditional=no @ winter or *:conditional=no @ snow is appropriate. Please, be careful in choosing the proper access tags as e.g. access:conditional=no @ snow includes ski which is allowed for certain ways. It is true that many routers do not support the conditional tags well but I would not use access=no plus positive conditional tags if the ways is open most of the year. Please always add the source for the restrictions to the changeset meta data.
The Feldberg region is quite tricky in finding the best fit of access tags and as far as I know there should be time-spans for most of the restrictions rather than “winter” or “snow”. As we are in Germany the restrictions need to be signed if not at every path at least at each way entering a restricted area forming a “zone” (except bicycle access on paths in the forest).
Lots of good tagging suggestions here, let me add one. There’s a snowshoe tag which is an access restriction. So in addition to conditional access tagging for foot you can say that a path is never allowed for snowshoe hiking:
foot = yes
foot:conditional = no @ snow
snowshoe = no
Also, the tagging alone won’t solve the problem unless routers honour it. Do you have a sense which routers (e.g. mobile apps) most people are using? Then it should be possible to contact the router developers, and ask them to interpret these tags. They don’t need to know if there is snow cover to show a warning message. For example when you are planning a cycle ride, Komoot will show warnings like “Cycling is not permitted along part of this route. You’ll need to dismount and push your bike”, or “The surface of a segment of this tour may not be suitable.” A similar warning could be shown during the winter months, such as “You cannot hike here when there is snow cover.”
Come to think of it: Would a restricted zone be respected by routers, similar to a military training range (I’m aware they would usually be fenced)?