US Trails Stewardship Utah Campaign - Let's Hit Pause

I am asking that OpenStreetMap US put on hold the Utah Campaign, and any other campaign they might be anticipating. As noted before, my work has uncovered evidence that there are a tremendous number of errors in at least some of the government trail data. The risk is just too great that this defective data will leak into OSM if the organizers go forward with their campaign. While many of you reading this are probably very careful mappers, past experience has shown that not everyone is - even when explicit instructions are given.

When the announcement came out about the campaign, I was in the middle of assessing the USFS trail data for Dillon Ranger District near where I live in Colorado. I have now finished the first phase of that assessment, and I found a ~50% error rate! That is right, half the trails had errors! In many cases matching up the government data with the spatially correct data in OSM can only be guessed at as the geometry is so different. I realize that the Dillon RD is in Colorado, and the proposed campaign is in Utah, but based upon my previous work - which also uncovered many problems - I strongly suspect that at least some of the data in Utah will be just as bad. I made this video overview of the situation: This initial assessment didn’t cover trails missing from the USFS data, nor errors in names, trail numbers, or allowed usages - but I know from past work that these types of errors occur too. I would hate to have the tagging in OSM that was carefully and painstakingly collected through field surveys overwritten by this bad data.

After making that video, I also discovered that in some cases a trail that the USFS says is managed by one ranger district, is 90 miles away in another district! In some cases trails are duplicated with multiple ranger districts claiming them. In some cases the geometry is duplicated, but the tagging (“attributes” in GIS speak), don’t match.

If this organized editing activity were to be proposed by an ordinary mapper, it would probably be shut down due to the poor quality of the data. Why should this be different?


I’m pretty sure that’s the point of having humans inspect data sets and improve the map. This isn’t really different from any other editing effort. If someone made an error while mapping, comment on the offending changeset.

If you want to get involved, get involved! The group meets regularly and I’m sure they’d be happy to have more hands helping out. There are quite a few folks that have invested quite a bit of time and energy working on this problem, and I am personally satisfied that they’ve been doing their due diligence in line with community norms. So no, we are not going to be “hitting pause” on it.


I watched your video and I definitely agree with your concern. I don’t think that the accuracy issues are a deabreaker, but it definitely deserves some more scrutiny since it sounds like the instructions will tell participants to mark existing OSM trails which don’t match official sources as access=private, which could be damaging to routing.

If “due diligence” has been done, how is it that the issue of government trail data quality not come up before?

I am taken aback by your quick dismisal of my well documented concerns. You don’t even want to find out for yourself what the truth is? What is the harm in a little pause to take a closer look at the actual data you will be asking mappers to work with? As the TIGER import showed, once bad data is in OSM it can be a long time before it gets fixed.

I thought it was informal=yes, but in any event, at least in the areas I looked at, there are going to be a lot of trails that are official marked otherwise.

Maybe I am reading into this sentence more than I should, but from the announcement post:

Where volunteers identify unofficial trails, mappers will be instructed to add attributes such as informal=yes and access=private as appropriate. These attributes will support navigation apps in determining which and how trails in OpenStreetMap are displayed to their data consumers.

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Cannot comment on the political issues, but it is much the same here in Austria/Europe: Governmental data absolutely cannot be blindly trusted. Especially when it comes to trails in the woods. The governmental ones sometimes are very accurate to the ground, but there are a staggering amount of errors, it sometimes makes me wonder, if they don’t do ground survey (which they do!)


This effort is over two years old at this point – the original Mappy Hour that spawned this effort happened in September 2021. I get that you’re not familiar with all the conversations and zoom calls and behind the scenes work by volunteers and you’re trying to digest a two-year-old effort based on a press release and looking at some trail data. I’m specifically dismissing your concerns because you’re choosing to throw darts based on a cursory review of data and a cursory understanding of what the group is trying to do.

I again reiterate the invitation (open to anyone) to get involved and actually talk to people rather than complain that you don’t like what’s happening and write walls of text about how everyone is getting it wrong.

Of course extant OSM trail data is better than a government data set – OSM data is crowd-sourced and government trail data isn’t. It’s also not an import, so the comparison to TIGER is more than a little silly.

So no – again – we aren’t hitting the pause button. But I encourage you to get involved.

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+1 :slight_smile:

Please excuse the +1 post.

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Cursory?!!! I have spent hundreds of hours analysing government trail data from many different agencies, as well as mapping trails in OSM, and attempting to provide feedback to government agencies! I worked with a local TV news station on a story about the problems with government trail data: Colorado preferred trail navigation app COTREX has its own flaws, hikers say - CBS Colorado. I am offended that you call that cursory. I have made many videos documenting my findings that I have posted on YouTube. Here is just one playlist:
I presented about my work at a major GIS conference this fall.
I research these issues in depth, often looking at documentation from the agency beyond their GIS data, as well as visiting many trails and taking geotagged phones of signs, recording GPS traces, etc. I am not “throwing darts”, I am only reporting the evidence that I have uncovered. Why does this bother you?

And zero time talking with anyone in the trails working group that you’re trying to “pause”.

As far as I’ve seen, the criticisms here are only about the source data sets and not about the quality of mapping that has been done in Utah.

These data sets have flaws, as all government data sets do, but they are useful. I’ve used them myself and I know that they can help diligent mappers produce excellent results.

If you’re seeing issues with the work done by US Trails Stewardship Utah mappers, comment on their changesets.

If there’s a clear pattern of poor quality mapping, document that and bring it to the attention of the campaign first, and the broader community only if that doesn’t produce results.

Otherwise, I say keep mapping.


So you take back that my review was “cursory”?

Regarding talking to the group, since I am not on Slack, I was not aware of what was going on.

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Very little discussion happens on Slack. The meetings happen on Zoom. Reach out to Maggie Cawley or Diane Fritz to get added to the calendar invite.


I’m confused. This talks about “launching” and was posted 16 days ago?

ZeLonewolf meant that the Trails Working Group has been working on the preparation to get to this point for the past two years.


I would also like to offer that the intent of the Utah Pilot is not to add any new trail geometries.

As stated in the announcement (emphasis mine):

volunteers will be tasked with updating attributes of existing trails in OpenStreetMap using official and approved sources. The Utah campaign will focus on improving trail attributes based on the trail tagging guidelines developed as a result of the trails tagging schema pilot in Washington state.

@tekim, I’d like to join others here in encouraging you to become involved in the Trails Working group if that’s of interest to you. It sounds like your extensive experience would be valuable to the group.


I will just say that I’m not at all surprised this campaign is receiving some pushback. Some of the language describing it like the snippet below (emphasis mine) is almost guaranteed to elicit a negative response from some portion of the mapper population:

volunteers will be tasked with updating attributes of existing trails in OpenStreetMap using official and approved sources

There is a contingent of mappers who do not like being told what to do, and certainly don’t like the implication that official or approved sources are superior to previously mapped data in OSM. I don’t think the folks setting up these trail campaigns and initiatives mean to communicate this, but it concerns me that words have not been chosen more carefully so the message would be received positively by OSM mappers. Perhaps this whole conversation could have been avoided if the above sentence had be this instead:

Mappers will update attributes on existing trails in OpenStreetmap using maps and datasets published by land managers as a reference.


Yes @ezekielf, good call. I’m certain that “tasked with” came purely from the fact that we’re using a tasking manager to help organize the efforts for those that want to partake. And yes, as was shared in our brown bag webinar today, we want folks to use all the reference data they have, including their personal knowledge, to create the best and most complete trail data possible.

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I disagree on this. I don’t like the implication that groups working in good faith to improve OSM need to craft their language to that level when the burden should be on people who have concerns to ask more questions about what those words mean rather than switching immediately to attack mode.

Word choice certainly matters, but I don’t see anything in the highlighted text that couldn’t be reasonably resolved in an open-minded discussion that starts with asking for more information, and I think that’s a fine bar for working groups and affiliates to clear in drafting language. Anything beyond that is on the people reading it, in my opinion.


I did not intend to imply any such thing. Of course nobody is ever required to carefully craft their language, but when you don’t then people can interpret your message differently than you intended. That’s all. I say this as someone who has spent a considerable amount of time participating in the trails working group (though I haven’t been involved recently). My interest is in seeing its efforts succeed rather than be met with pushback and mischaracterization simply because the messaging stepped on some obvious OSM landmines.