Not formally established

Please somebody fill me in - I do not understand what the words in the title of this topic mean.

A week ago, they got added to the description of the informal=yes tag in the wiki by @dieterdreist and in a similar manner to informal=no

Do we now have to look up paperwork to decide, if something is informal? Do operators now have to show license? How is that supposed to make mapping easier?

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That tag was created to distinguish a “desire path” or “social trail” from ones authorized and maintained by land or park management. The easy way to tell is to look for official trail signage and/or information boards that show official trail maps. If a trail is signed with official signs or shown on an official map then it is not informal.

Trail signs or information boards should be pretty easily noticed while mapping a trail system.

Likewise, if a trail just “peters out” or is an obvious shortcut down a steep slope to a stream or lake it is very likely to be an informal trail.

If you would like more information about why this tag was developed you can look at the US Trails Access Project wiki page.


This makes sense, although at the same time it creates the issue that several mapped paths, usually don’t have such signage or aren’t recorded in official maps/databases, which would make them informal. In my opinion, it would be much easier to tag a formal path rather than informal, mainly to how a typical user will see and try to map such path.

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The issue with tagging a trail as formal or authorized is that there were thousands of trails mapped before the problem with informal/unauthorized trails was identified. If by some fiat process it was decided that for a trail to show up on a hiking map or app it had to have a “formal” tag there would have been no trails to show until a lot of remapping had been done.

I strongly suspect that there are many more miles/kilometers of formal, managed trails than there are of informal or desire trails as most desire trails tend to be short. So you would likely need to add a formal=* tag to more objects than if you are marking desire trails with an informal=* tag

There is key informal=no, I was intrigued by that. But with the recent changes to the definition, I am at a loss of what informal actually means.

Informal history of documentation reaches back until April 2011. Can you show evidence of your proposition?

I think that there are a couple of points worth making here. One is that I suspect that the reason for this thread wasn’t asking what a “desire path” or “informal trail” was, but instead why the language “Not formally established” was used to try and describe it. It’s not great when you need to use three words to describe one; it’s even worse when you get it wrong.

From a UK perspective, the vast majority of what Americans might call “trails” were “not formally established”. In England and Wales, there has been a process to classify them and attach an appropriate legal status to them (still ongoing). In Scotland the rules on land access are more sensible but there there is also an ongoing project to classify them - again, the classification project is of ways that in the vast majority of cases were not formally established but are not in any sense informal.

The other is that while OSM US’ trail access project is extremely useful in helping e.g. app developers understand what they should and should not show, some of the language was not unnaturally written from a very US perspective. As an example, this (mentioned in this diary entry) is an “official” public bridleway… There are no posted signs or markings, there’s no text on the official website, but it does appear on UK Ordnance Survey Maps (and in the local authority data I linked to earlier) and is very much an “official” route - even though there’s no sign of anything on the ground.

What this means in practice is that OSM communities around the world are going to have to decide what is “informal” according to their own local laws and their own local customs. In this example, I’d suggest that if a herd of ramblers were to re-establish the bridleway route over the moor the resulting path would not be “informal”. That doesn’t mean that it isn’t worth mapping “genuine” informal paths (this one not far away springs to mind).

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By the time that the “Key:informal” page was created in April 2011, there were already some 889,000 highway=path ways stretching 258,823½ miles (416 536 km), including 49,900 ways stretching 22,027 miles (35 449 km) in the United States alone. It was not until mid-2019 that informal=yes usage passed 5,000 ways.

In any event, passive voice may be causing some confusion here. I suspect @n76 isn’t referring to @dieterdreist’s initial documentation. Rather, lots of trails had already been mapped and presented to users by 2016 or so, when others identified a problem with social trails in the U.S. and various community members from around the world insisted on a mix of informal=yes and access=no as the solution. Even more trails had been mapped and presented to users by 2021, when U.S. trail managers’ frustration with OSM-based applications boiled over and we began to prioritize the problem.


In Austria the two top rambling associations manage 26.000 km (Alpenverein) rsp. 20.000 km (ÖTK) of paths. Austria fits 117 times into the area of the United States. Those 35.000 km in the US back then might quite well have been all informal=no :wink:

This unfortunately does not work here. The official map that is available as a backdrop in iD and JOSM contains lots of informal paths. In places, there is not even a path on the ground.

This government data sometimes gets used to settle legal disputes. I do not consider it wise to burden openstreetmappers with such issues, as the recent change of the wiki documentation requires.

Maybe some other extra clause, informally established or maintained could serve all interested parties? Where informal maintenance mostly means voting with the feet / trampling.