Talk:Proposed features/Hazard warning

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Also for ways designated "on own risk"?

I recently found several forest paths which were explicitly designated like "pedestrians entering on own risk" (e.g. due to decayed trees), wondering how to tag this. Depending on your risk/liability preference, access=yes/no both did not fit. Something like "access=ownrisk" was my proposal. Please consider if this could also be covered better in this proposal, e.g. by a value "caution=designated".--Rs 21:22, 14 November 2008 (UTC)

I thinks your suggestion "access=own_risk" fits your purpose better. caution tries to indicate a definite hazard by marking a node, while you want to map something concerning access to the way and marked by a sign, on the whole way. --Nop 22:44, 14 November 2008 (UTC)

A hazard can just as well be a way, just think of a road along a cliff side, shouldn't the entire length of the cliff side be tagged with a warning that your car might plunge to the abyss if it skids of the road? Or what about an area with many sharp curves in the road, wouldn't that also be more appropriate to tag along the way? To make it a node only will reduce it to only cover dangerous crossings, or other hazards limited to single points. --Skippern 18:08, 29 November 2008 (UTC)

I have extended the proposal to include ways and added more emphasis on streets. But if we include street signs, would it make sense to also tag the exact type of sign (caution=sign, sign=falling_rocks) with a large set of values? Or would it make sense to just tag the existence of a sign (caution=falling_rocks, sign=yes)? --Nop 23:59, 29 November 2008 (UTC)
sign=yes is ambiguous for many ways; does it mean there's a sign for the street name, street ref, hazard, or something else? Perhaps something like (hazard=falling_rocks, hazard:signed=yes) instead? AndrewMcCarthy 09:53, 30 November 2008 (UTC)
You have a point there, this would be very ambiguous. This leaves the first possibility to tag signs as a special case (caution=signed, caution_type=falling_rocks) or consider them the rule (caution=falling_rocks but caution=generic, caution_description=Barbed wire on the ground. --Nop 23:15, 4 December 2008 (UTC)

Should be applicable on way too.

In Sweden, at least, warning signs could be referring to a stretch of the road ahead. Like warnings for wild animals.--Bengibollen 00:01, 23 November 2008 (UTC)

  • Ok, I see now that the author meant this tag to apply mostly to hiking trails. But I believe it could be used more broadly and include hazards on roads as well. --Bengibollen 00:06, 23 November 2008 (UTC)
    • Dangerous curve
    • Steep edge
    • Cliff side road
    • Wild animals in the road
    • Access point for large or heavy vehicles

Most of these would only apply for roads with motorized traffic. --Skippern 18:11, 29 November 2008 (UTC)


hazard= seems to be slightly more common in existing tagging than caution= Ojw 13:58, 29 November 2008 (UTC)

Second that, just a simple hazard=* with freetext, for warnings in multiple languages use :ISO code, for instance hazard:pt=* --Skippern 18:03, 29 November 2008 (UTC)
I disagree. It appears that caution is the common term used for warning traffic signs. A caution sign by the street warns about a hazard, so a caution tag on the map should warn about the hazard. --Nop 23:50, 29 November 2008 (UTC)
A hazard can also be something not signposted - a very short acceleration lane or a blind curve on a cycleway. Alv 23:54, 29 November 2008 (UTC)
We're marking the hazard itself, not the roadsign ("caution sign"). If this proposal is about marking the signposts, then let's change it to caution_sign= or signpost:caution=. Ojw 09:01, 1 December 2008 (UTC)
Keep it simple for the mappers, focus on the actual data (hazard in this case) and let signs be another issue. I will not go around tagging all the signs, but rather tag the information that the sign is put up to inform about. I rather mark the curve as a hazard than put up a sign on each side saying the curve is dangerous. --Skippern 10:21, 1 December 2008 (UTC)
The idea of the proposal ist not tagging signs, but tagging locations that require passing them with caution, both marked and unmarked by signs. In the end the name of the tag caution/warning/hazard/danger seems to be rather a matter of taste, the usage being the same, with my preference still going towards "caution". So how do we solve that? I want to avoid a stalemate where one half of the people votes against the proposal if it is named "caution" and the other half votes against if it is named "hazard" so it can never pass. --Nop 23:20, 4 December 2008 (UTC)

freeform text?

I'd prefer to avoid freetext where possible. Defined values (defined on the Wiki page as needed, I suppose) like sharp_bend, falling_rocks, etc, can be rendered consistently and translated automatically. AndrewMcCarthy 10:10, 30 November 2008 (UTC)
The reason I suggested free text is that we only need to render a marker (warning sign?) in the map, and the text will be available if we query the specific hazard, for instance a map navigating software should be able to display the warning in some time before approaching the danger. I agree that there are some adventages of using pre-defined values, such as having pre-recorded audible warnings linked to a fixed value instead of free text which would require speech synthesizing or other similar techniques to give an audible warning. But as the range of warnings can be waste, and users would need to refer to the wiki for each time he enters a different type of hazard. This will severly complicate offline editing. --Skippern 10:14, 30 November 2008 (UTC)
If you do start working towards a list of values, I'd like one included for the UK signed "Unsuitable for Motor Vehicles" warning that I'd like to use this tag for at some point. EdLoach 09:20, 2 December 2008 (UTC)
What about having a list for hazard=* with an optional freetext=* for "other" hazards? That way we are not locked if there are no suitable hazards on the list. --Skippern 11:26, 2 December 2008 (UTC)
The range of different hazards you might encounter is just too wide and unpredictable to make a set of predefined tags the rule. On the other hand it would be useful for hazards marked by signs as the signs are already defined. So we would have to go for a combination, either with the free text being the standard case (caution=signed, caution_type=falling_rocks) or with the predefined tag being the standard case (caution=generic, caution_description=Barbed wire on the ground.) --Nop 23:23, 4 December 2008 (UTC)
One way is to have the hazard itself be a freetext, but having a set of predefined values for signs and other things the render or routing program might need or use. For example hazard="Dangerous courve" and hazard_sign="courve" hazard_id=## number from a list. --Skippern 10:29, 5 December 2008 (UTC)
I like the idea of two tags, the proposed caution=<description> accompanied by caution_sign=<list element> where required. So I thought about extending the proposal to include a tag for traffic signs. But when looking at the official traffic signs (German version here, I noted that there are not too many signs of interest here. There are other tags for street/railroad crossings, curves, inclines, tunnels, traffic lights, narrow and uneven pavement. Construction is only temporary. So what does that leave us with as caution_signs?
That's the relevant, official signs I found. If there are other signs, they seem to not to be in the standardized catalog but individual and thus are better tagged with a freeform text. Any more suggestions? I think animals_crossing and crosswinds are already pretty weak and are one the list rather for completeness. Comments? --Nop 07:11, 8 December 2008 (UTC)
Where is the curve tag? Have looked for it, maybe been looking the wrong place.
Ignore those that already are covered. --Skippern 08:49, 8 December 2008 (UTC)
Curves are not tagged, but are contained in the geometry of the way. The proposal to tag inclines in more detail was rejected due to this information being contained in terrain data. So I would not propose to tag something that is represented by OSM geometry. I also don't understand the relevance of heavy_goods_vehicles. --Nop 13:43, 8 December 2008 (UTC)
On my passage to the airport I pass signs of the type "large vehicle entrance" or "heavy vehicle entrance", these signs are shaped as warnings, and these entrances are in locations where the road is curving. These vehicles will need a long time to accelerate to the speed limit of 80kph, and since you have a limited length of view ahead, this is a hazard to the traffic. There might be other reasons than sharp curve that makes a curve dangerous, for instance counter dosage will make a slack curve on a high speed road dangerous. --Skippern 13:06, 13 December 2008 (UTC)

Vovkav 19:16, 21 February 2010 (UTC): The text could be freeform, but have as many predefined short values (in non-language-specific qualificator) as possible.


Actually thinking about it, it can also apply to an area. If all the paths in a forest have the same warning, why not put it as an area tag on that forest? In that case a route planner should see any entry point to that area as a place to put the warning, and it can also be used as a tool to avoid such hazards. If you know it is dangerous to pass area X, why not drive past Y instead as that is a much safer route? --Skippern 11:38, 2 December 2008 (UTC)

I see various problems with extending this idea to an area
- there is very little use for this, I can think of no application where all ways in an area would have exactly the same type of danger and that would not be marked seperately, e.g. a military shooting range.
- This would be very confusing for a user, if you do not check the tags of an area, any new way you add would be automatically considered hazardous even if this is not your intention
- as soon as there is the first exception you have to re-tag the area as well as all other ways inside
- it is very hard to detect and render this condition, as far as I know, no renderer has any concept for way segments inheriting a tag from intersecting areas.
So I would stick to nodes and ways with this proposal. --Nop 23:28, 4 December 2008 (UTC)
I see your point. --Skippern 10:17, 5 December 2008 (UTC)

I would just like to point out that I do see the need for an area "warning" tag, and I'm not sure whether there is one:

  • Crime hotspots
  • Areas where drug use is tolerated (discarded syringes pose a passive threat, while the drug users or those seeking to profit off them might constitute an active threat)
  • Forests known to harbour certain infections (Rabies, malaria)
  • War remnants (landmines, bombs, depleted uranium)
  • Soil contaminated with heavy metals (Cadmium, mercury, old landfill/chemical sites)
  • areas where balloons or helicopters operate
  • flash flood risks
  • tidal waters
  • open sewers (smelly, but not necessarily dangerous)
  • swamps
  • nuclear fallout hotspots

I'm aware of examples of:

  • forests marked off-limits because of rabies
  • areas considered inappropriate for under-18s
  • bombs left in place after WWII, with the area marked off-limits
  • open sewers with warning signs
  • heavy-metal-contaminated soils marked off-limit

I suspect there are still some lepers' colonies, or the modern equivalent. Keep in mind islands declared off-limits for decades because of anthrax experiments, too.

Rnmx 13:46, 24 October 2009 (UTC)

To add to the list, on marine charts dumping areas for explosives, safety zones around well heads, platforms and FPSOs might be marked with warnings, in some cases with texts such as "unexploded ordinances", "anchors and chains", "subsea obstructions", and in some cases entry into such areas only are allowed after obtaining permission from some sort of authority.--Skippern 13:56, 24 October 2009 (UTC)
Two more I thought of:
  • undercurrents or sub-surface water intake making swimming dangerous
  • suicide hotspots
I do think the latter kind of area should have markup of some kind, especially where suicide intervention is visible (nets, cameras, crisis phones, crisis centres). If nothing else, we can trap certain searches on the main map server "suicide opportunities near Westminster, UK"? ...
Internal border controls and forbidden cities also come to mind, though in those cases, it would probably make most sense to markup the actual control facilities.
Rnmx 14:25, 24 October 2009 (UTC)
One more (though, again, this might be a newbie question if there's a tag I just haven't found yet): photography prohibited. That's still common, I believe, near dams and nuclear power plants, but also true near some psychiatric hospitals, addiction treatment centres, and near baby hatches.
Rnmx 14:29, 24 October 2009 (UTC)