Proposal:Difficult Passability

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Difficult Passability
Proposal status: Obsoleted (inactive)
Proposed by: KonfrareAlbert
Tagging: dif_passability=no, dense_vegetation, fallen_tree, with_precipice, waterway_crossing, hands_needed
Applies to: node, way
Definition: Objective difficulties in a path (or highways) with verifiable situations

Rendered as: no render
Draft started: 2012-10-4
RFC start: 2012-10-8


I want that people can discern between trails without obstacles or objective difficulties (for example for people with less mobility, walks with children, etc.) and adventure trails. Also the key must be verifiable and for this motive I assigned values that I think that are concretes values.


The goal of this tag is that navigation applications can avoid trails with some difficulties when calculating routes. Some navigation applications like OsmAnd can avoid routes with bumps, tolls or ferries for calculating routes for vehicles, but not can personalize calculating routes for pedestrians. I proposed in OsmAnd's forum (see the discussion) that calculating routes could include options to avoid the tag trail_visibility=bad, because I was using this tag for trails with much vegetation that could be hard to cross in some cases with risk that suffer scratches for brambleberry (for example). This trails are historic rural trails abandoned. I understood quickly that trail_visibility=* was not the correct tag for my proposal. In discussion appeared some tags but none seemed useful (view Tagging content) I was very confused with the development of proposal, and a Proposed_features/Passability (Abandoned) expressed very different concept. A simple blog gave me an idea: «Objective difficulties». This approach allows trails with concrets impediments be tagged in a verifiable form for passability.


In the municipally term of La Palma de Cervelló (5,47Km², a very little municipally term in Catalonia, wikipedia), I calculate that there are approximately more than twenty highway=* (paths and tracks) that could be tagged with dif_passability=no, ten highway=path (or puntual part of this) that could be tagged with dif_passability=dense_vegetation, three dif_passability=fallen_tree that impede the passability could be added, two highway=path could be complemented with dif_passability=with_precipice, ten dif_passability=waterway_crossing could be localized in highway=path that cross streams and torrents, and two nodes with dif_passability=needed_hands could be added. There are much trails mapped and the pedestrian navigation experience improve with this key. I think therefore that this key could be very useful, and could be apply to a lot of places of the world, for example the key dif_passability=fallen_tree could be more used when a disaster occurs like a hurricane, earthquake... (La Palma de Cervelló was affected for extratropical Klaus cyclone in January 2009 and there were hundreds of trees fallen, a lot of them impeded the passability in trails). In Catalonia there are hard wind frequently, topcoat the Tramuntana wind (see the Wikipedia).


The key refers to highway=path and highway=footway for pedestrians, but these difficults in passability will be extensives to bicycles, road vehicles and horses. Therefore the key would be compatible for other highway=*.

Key=Value Element Description Photo
dif_passability=no way No static elements in the trail (in front or around) that difficult the passability for a pedestrian. You can walk erect and with stretched arms and in beeline, evidently following the path traced ;)
The path climbs - - 1065463
Single track climb - - 614387
dif_passability=dense_vegetation node, way There are big shrubberies, brambleberry, very high and dense grass, big branches, lianas, etc that limited the personal space and force you to duck or to dodge, and you must walk careful. There are risk of scratches in arms and legs, and stumbles. If you can walk erect and with stretched arms and in beeline, in this case you never must not apply this value.
Dense vegetation in Healaval Forest - - 960081
dif_passability=fallen_tree node There is a big fallen tree that completely hinders passability, and you only can continue the path if you cross the tree (cross it above or below). This key could be complemented with key abandoned=yes if the fallen tree takes a long time is there. If there is a fallen tree that permite the pass (in or around the trail) you never must not apply this value.
Fallen Tree - - 288010
dif_passability=with_precipice node, way There is an important precipice alongside the trail (at least one side) that your eyes can't avoid see if you look forward (for example, because you can't move over away). When you are walking in the trail you can see the falling. There are a minimal risk of falling (major for people with a tendency to fall over, small children, etc.), but it's an important difficulty for people with dizziness. If you can move over away from the precipice and take out it of your visual field, you must not apply this value.
View down the back wall of the Porth Saint cove - - 866608
dif_passability=waterway_crossing node, way You must cross a river, stream or torrent and you only can do this if you jump, or if you walk stone by stone. If seasonally the waterway haven't water, you can combine with the intermittent=yes. If you can cross the waterway without changing the natural form of walking, you must not use this value.
Footpath crosses stream south of Hay Wood - - 1586453
dif_passability=needed_hands node, way In front of the trail you must use hands for continue the route. It can be because there is a big stone, a margin that must be crossed or simply the terrain begins to be very steep. This key could be complemented with the key incline=* in percentage or degrees. This difficulty can't be avoid in this trail for continue the route, in this case you must not use this value.
Climbing Spearhead Gully - - 1010937

Keys appeared in OsmAnd's forum (see the discussion) for my proposal were:

  • trail_visibility=*: The key only refers to orientation problems, not to real impediments. People with less mobility perhaps could move without problems in a trail with bad visibility, but a felled tree will be surely an important problem in route, for example. This key has the problem of Verifiability.
  • sac_scale=*: Is a general key (a good key!) for hiking trails, but it don't specify concrete impediments. This key has the problem of Verifiability.
  • smoothness=*: Only refers to the quality of the road, not to elements around the road. This key has the problem of Verifiability.
  • dangerous=*: Not created key. I think that key could be excessive because the proposal is to mark impediments, not the risk. These type of key (in relation with passability) could have values like minefield or hunting area that are dangers real.
  • tracktype=grade5: Only refers to the quality of the road, not to elements around the road.
  • abandoned=yes: Not always that a trail is abandoned we find difficulties on passability or impediments.

I think that the keys trail_visibility=*, sac_scale=*, smoothness=*, tracktype=grade5 and abandoned=yes are compatible with the key dif_passability=* proposed. If values are analized, we can see that:

Applies to

This key always must be in a way with the key highway=* (generally in highway=path, highway=footway, highway=cycleway or highway=bridleway). The key dif_passability=* could be a node in this way, or a key added to highway=* in the way or in a stretch of the way (if the difficulty is along five meters). The key dif_passability=no can't be a node because it would be absurd, and I consider that the key dif_passability=fallen_tree must be only a node because always is a puntual obstacle. If a long fallen tree obstaculizes two trails, I think that the best option would be add a node with dif_passability=fallen_tree in each trail. If we mark the fallen tree like a way that affects two trails, then we lose the calculating routes proposal for avoid obstacles.


I think that this key perhaps no needs to be rendered.

Features/Pages affected

If this proposal is approved most of the highway=* pages must includes this key for add.


I'm not sure that this key could be the perfect solution for my proposal, but I'm very interested in the comments, and I desire that if is rejected perhaps this proposal helps somebody to find a best solution.