Iron Canyon - trail on OSM?

[Nate U]

Howdy folks.

Anyone ever been up Iron Canyon in the far west of the Gabes?

OSM shows a trail going up the side of it. FS map shows a partial trail starting up the canyon then ending. I'm wondering if there is anything left of this? Wouldn't mind bagging Magic Mtn via. this route if there is something to follow, old and overgrown and all.

This is definitely a David R. kind of question!

Related, anyone ever been up Sand Canyon, one canyon to the south? No trail marking at all on that one.

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[dima]

You can look up the history of this way in osm:

• https://www.openstreetmap.org/way/968872534/history
• https://www.openstreetmap.org/changeset ... /-118.1034

I would guess that "add iron canyon trail based on gpx of usfs data origination" means he copied the USFS map, but

• The latest USFS and USGS maps don't have the full route (I don't feel like digging up the older maps)
• The portion of the latest USFS map that does show the trail doesn't match his OSM route

So I don't know. If nobody here has been there, I'd just send leefrance a message, and ask.

[Nate U]

I forgot about how you can look up the OSM edit history, thanks Dima!

I checked it out on that USGS 3DEP viewer and there is no evidence whatsoever of a trail, so I have lots of doubts there is much of anything there.

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I suspect leefrance glorified his bushwhack with an OSM upload of his GPX track, but I went ahead and messaged him.

[dima]

The high-res DEM I'm looking at actually shows a clear trail where leefrance said it was (whatever caltopo is showing isn't the "good" stuff). It's faint in places (so probably long-abandoned), but the trailbed is there.

[Nate U]

I zoomed in further, and darned if you aren't right! A faint trail indentation along the slope! Ok this could be worth investigating on the ground.

[Sean]

People adding trails to OSM based on ancient FS data are a problem, just like the FS is a problem for not updating their ancient data. These people live in the fantasy world of a bad map, and they don't care much for objective reality, upon which good maps are created and maintained.

[dima]

I don't think it's a huge issue for OSM, actually. At least in the San Gabriels, I don't see a lot of bushwhacks being mapped or other maps being copied blindly. It happens, but not often, and then it gets fixed quickly. In this case, when Nate goes out there to confirm that this is actually not there anymore, we can mark that route as abandoned, and we'll be done.

As for the USFS maps, they're indeed a problem if you don't take your grain of salt when looking at them. But really, these are all made by humans, and humans make mistakes or maybe have weird incentives, so the grain of salt is always appropriate. Does google maps still say that hwy 39 connects to hwy 2 at Islip Saddle? Looking... Yes. Yes it does.

[Nate U]

Although poorly updated, I find the FS maps useful for place names and historical info, with the poor updates actually making them more valuable in that regard. And they are visually cleaner than USGS topos. The more exploring and research I do the more different resources I draw upon depending on what I'm trying to accomplish.

[Sean]

When these old trails get restored, it's hard to miss, and new GPX will find its way to OSM. But I can't find an official trail designation for Iron Canyon, so it probably won't be restored by a sanctioned crew.

[dima]

When these old trails get restored, it's hard to miss, and new GPX will find its way to OSM. But I can't find an official trail designation for Iron Canyon, so it probably won't be restored by a sanctioned crew.

Oh, that's really interesting. Are you talking about the official forest service trail inventory list? I was assuming that their official list is quite literally what appears on their maps (the Iron Canyon trail is on the USFS map, at least partially). You're saying that something might not officially exist and yet appear on their maps? And vice versa?

[dima]

Also for the record, there is a way to tag abandoned things on OSM. Objects with these tags won't appear on normal maps, but are helpful for future edits. So if somebody here travels that route, and decides that it is very much abandoned, we should change the tags. Instead of removing it entirely. And we should tell leefrance.

[Sean]

Oh, that's really interesting. Are you talking about the official forest service trail inventory list? I was assuming that their official list is quite literally what appears on their maps (the Iron Canyon trail is on the USFS map, at least partially). You're saying that something might not officially exist and yet appear on their maps? And vice versa?

Well, if you go to CalTopo and select the Forest Service topo layer, the Iron Canyon trail has no trail number, no name, and it ends before the 2600' contour. That probably means it's a holdover from an old USGS survey, and the FS doesn't recognize it as an official FS trail but hasn't quite expunged it from the map. If that's the case, they wouldn't approve work on it. Also, the TH appears to be 500 feet outside the forest boundary, which wouldn't help it become an official trail in the future. In general, approved fire roads or trails have number designations. These don't always appear on maps, so I'll have to double check with a trail boss that this trail isn't on the FS list.

[Nate U]

from leefrance:
Apologies but I can’t really speak to the current condition of this one. I seem to have added the trail to osm via a usfs data file and it looks like it’s been updated for accuracy since then. So I’m really not sure!

I reached out to the updater, AmpereBEEP, and will let ya'll know if I hear anything.

Sean I think could very well be right about the trail just getting copied from USGS survey onto the FS map, as the CalTopo scanned topo layer shows the truncated trail as well.

And yet, we see a trailbed in the topography.... so there is *something* out there...

Once it gets cooler this fall I'm going to attempt a point-to-point Magic Mountain bag via tracing this Iron Canyon trail-bed evidence / OSM path. The return route can be flexible per what anyone else who joins me might want to do. I'll put out an invite to ya'll when the time comes!

[dima]

Yeah. So mystery solved. It used to exist in some form, and today it's exists about as much as those phantom trails that I'm seeing on the new DEMs. I'm going to mark that whole thing as abandoned

[dima]

Updated. Looking at the DEMs tells me that closer to Magic Mountain this was a road, not a trail. The DEMs also show multiple other abandoned routes in that area, that are as worthy of exploration as this.

[Sean]

And yet, we see a trailbed in the topography.... so there is *something* out there...

Looks like that whole canyon burned in the Sand Fire. You might actually be able to follow the trail if there aren't too many downed trees and thorny stuff.

[Nate U]

From AmpereBEEP, who updated Iron Canyon trail on OSM:

Hello! I have not hiked the trail nor visited the area, so I am not sure what the conditions are on the trail. I moved it several years ago in order to improve the accuracy of what was visible on the surface while mapping out some proposed High Speed Rail tunneling in the area. Hopefully you find out the conditions!

My guess is AmpereBEEP edited the FS map info that leefrance had uploaded to match the aerial trailbed evidence recently exposed by the Sand Fire.

Kind of interesting they were mapping high speed rail tunneling!

[Sean]

From AmpereBEEP, who updated Iron Canyon trail on OSM:

...I moved it several years ago in order to improve the accuracy of what was visible on the surface...

Alas, a mapper who cares about reality! That's probably a fine track since he was tracing from aerial imagery.