Backcountry / Skitour -- Survey, how do you map?

ezekielf · 2022-11-13T21:30:17.359Z

ScottNelson:

piste:grooming = backcountry is a bit unnatural for this use case, because in the united states and canada “backcountry” means “no ski patrol / avalanche control”, which really has nothing to do with grooming

I agree. The piste:grooming values for downhill runs feel awkward. I think they are basically supposed to mean:

classic: standard coduroy grooming
moguls: intentionally created moguls, or almost always has naturally developed moguls
backcountry: ungroomed

If I had created the tag I’d have made the values groomed, moguls, and ungroomed. No sense confusing things with the backcountry connotation.

flub · 2022-11-17T09:56:56.561Z

My touring experience is mostly in the Alps outside of resorts, and I haven’t done much mapping partially because IIRC last time I looked for guidance there was very little. With that background and reading what’s said here’s my opinion.

I’d only map somewhat well-known tours. You can ski so many things, but looking at a map you want to know the common stuff - how to approach or escape your adventure if you do something weird or just do a classic tour. I think an example of this are the Swiss ski-touring topo maps where they do this.

I’d tag piste:type = skitour but I don’t think I could be bothered with tagging the grooming at all. Ungroomed implies usually something resort-based that’s not groomed and thus turns into a mogul field. If there is a section on a cattrack because of a hut supply or so then I think that should be mapped as some kind of track and not as a skitour. Similar if a tour starts or ends on a piste - just let the piste track take over there. If you need to link a tour together from different segments then maybe a relation is better?

Most ski tours can be ascended and descended. Some are only decent but those are the exception and there’d I’d expect to mark oneway = yes.

Looking at ski-tour maps there usually are two kind of lines: solid and dashed. The latter indicates difficult terrain usually, this could be many things and you’d be looking for other clues on the map or look for other literature. Can range from “often not much snow”, to “difficult crevasses” to “climbing a rocky ridge”. Some kind of way to indicate those tricky sections - and get them rendered - would be nice.

A way to tag the “typical” duration would be nice.

Lastly it would be nice to be able to also tag the difficulty level of a tour (outside of the tricky sections mentioned above). The SAC (Swiss Alpine Club) have a well known scale and most others in the alps seems similar-ish that they have a single grade in 5 to 8 steps that includes some guidance on steepness, exposure, narrow or other technical bits etc.

I’d be great to have some page with dedicated guidance on how to tag ski tours!

flub · 2022-11-17T10:07:28.972Z

To be fair I wouldn’t mind using entirely different tags from piste:*. Someone looking at a piste map in a resort should probably not be shown skitours. And using “piste” for something that has nothing to do with pistes is a bit odd.

yvecai · 2022-11-17T11:03:48.561Z

flub:

Lastly it would be nice to be able to also tag the difficulty level of a tour (outside of the tricky sections mentioned above). The SAC (Swiss Alpine Club) have a well known scale

On the wiki, the piste:difficulty definition for piste:type=skitour is exactly that.

Hungerburg · 2022-11-17T11:14:51.707Z

Skitour fits fine here Key:piste:type - OpenStreetMap Wiki

When the descent gets mapped though, automated consumers might have problems telling downhills apart. The survey brought up the operator and patrolled attributes. Will that be good enough?

yvecai · 2022-11-17T11:49:11.160Z

Hungerburg:

The survey brought up the operator and patrolled attributes. Will that be good enough?

It seems to me that yes, it should be good enough.

flub · 2022-11-17T19:41:53.454Z

oh nice! didn’t realise. so that part exist already then. thanks!

flub · 2022-11-17T19:45:26.029Z

So sounds like most things I was wondering about already exist more or less. No reason not to map more tours.

Hungerburg · 2022-11-17T19:47:36.620Z

These attributes rarely set here. There is one more indicator, when a backcountry downhill is part of a piste type site relation, it is likely in a resort, patrolled and has an operator. Might need a bit overpass turbo to affirm, should not be hard though.

yvecai · 2022-11-17T21:09:30.000Z

One attribute I see in the data is often piste:difficulty=freeride.
I wonder if it is equivalent to “piste:type=downhill + piste:grooming=backcountry”.

Hungerburg · 2022-11-17T23:17:14.137Z

Browsing with overpass gives very unconclusive results. At least, I learned, that there is one such in my hometown - Way: 587946839 | OpenStreetMap - it is even publicly announced by the resort as such. Other resorts near by also advertise freeriding possibilities.

Freeriding can be a reason to go on skitour, but obviously, one can freeride from the cable car station just as well.

Fritzifuchs · 2022-11-18T20:14:55.098Z

I ski almost exclusively alpine. In the fall, I always try to map the piste map as best as possible in the ski resorts where I will be next.
The ski routes typically indicated in yellow / orange in the piste map cause me difficulties. (Which are marked with diamond shaped signs on the slope).

Because these are not official slopes and are not groomed by the Pistenbully, I would map them as piste:difficulty=freeride and piste:grooming=backcountry.

But for freeride the wiki description doesn’t quite fit (Why does the slope have to be 50-55 degrees for freeride?) and it seems to me that grooming backcountry should only be used for ski touring, since it is shown on the OpenSnowMap with the circles for ski touring and not for alpine skiing.
Why is that?

I can’t map the completely free off-piste trails, since I don’t ski there and don’t know them.

Hungerburg · 2022-11-19T00:16:48.621Z

Fritzifuchs:

Why does the slope have to be 50-55 degrees for freeride?

Because otherwise, you would get stuck in hips deep powder But yes, a bit less should be fine for knee deep powder just as well. 60 degrees is practically a wall. Consequently, there never will be much snow there OSM wiki seems to be addressing world class elite freeride skiers, that jump down rocky terrain. 30+ degrees will be good enough in many conditions to have fun.

yvecai · 2022-11-19T05:10:19.843Z

For piste:type=skitour, piste:difficulty=* wiki definitions refers to the SAC scale for ages, hence the 55°. Maybe the link should be made more visible.

Swiss Alpine Club SAC

Grading systems

Schwierigkeitsskalen aller Bergsport-Disziplinen in der Übersicht.

Fritzifuchs · 2022-11-19T10:34:52.300Z

Ski Route Saalbach Hinterglemm903×559 87.3 KB

And here is already the big difference:
I try to find a good mapping for Alpine skiing (piste:type=downhill).

The problem seems to be that for both piste:type=downhill and piste:type=skitour the difficulty is given with the same nomenclature (piste:difficulty=).

Now when I try to map an official ski route specified by the ski resort, this is definitely piste:type=downhill. The difficulty is typically not specified for these routes. (Very very few resorts nevertheless classify them with blue-red-black).

Since these ski routes are given without rating, I tag them with “piste:difficulty=freeride”. In german, the translation for this is even “off-piste”, which fits wonderfully with the route.

So my suggestion would be to rename the existing Freeride to “Exceptionally Difficult”, which is what it actually represents.
…and to introduce a new value for such marked ski routes that have no rating. Whether the designation “Off-piste” would make sense, which actually means “Off-piste without any further rating”, remains to be seen.

The photo shows the piste map of Saalbach Hinterglemm. There are several such ski routes there. These are far from jumps over cliffs or 50% drops.

Hungerburg · 2022-11-20T00:17:28.203Z

I am at a loss just the same. Nowhere does the SAC call the skitours between 50 and 55° slope, where - during ascent or descent, quote - falls often fatal, by the name “freeride”. They call them “Exceptionally Difficult”, c.f. https://www.sac-cas.ch/fileadmin/Ausbildung_und_Wissen/Sicher_unterwegs/Sicher_unterwegs_Skitour/2020_Skitourenskala_EN.pdf Perhaps, the OSM wording comes from the term free-climbing? There its used like that. But in skiing, freeride means ungroomed backcountry downhill, IIRC.

yvecai · 2022-11-20T06:58:04.713Z

‘freeride’ is not a word, it’s the value of an OSM tag.

I understand piste:difficulty=novice/easy/ … /freeride/extreme is intended to be a progressive scale that was later applied with the same values for piste:type other than downhill.
Could have been piste:difficulty=1/2/3/…

Now piste:difficulty=freeride stands out from the list of values, it is something different in natural language.

A bit of archeology:
The value difficulty=freeride appeared on the wiki in 2007, associated with european ‘yelow pistes’.
https://wiki.openstreetmap.org/w/index.php?title=Piste_Maps&oldid=43021

The first definition of piste:type=skitour:
https://wiki.openstreetmap.org/w/index.php?title=Piste_Maps&oldid=363081#Type

And the piste:difficulty applied to skitour baxk in 2009:
https://wiki.openstreetmap.org/w/index.php?title=Piste_Maps&oldid=378735#Difficulty

So, my understanding is that applied to piste:type=skitour, piste:difficulty=freeride just means SAC “AS”, ausserordentlich schwierig = “Exceptionally Difficult” in OSM tags. Nothing to do with natural word ‘freeride’.

yvecai · 2022-11-20T07:54:47.437Z

Mappers seems to follow this scale when they bother to map piste:difficulty on skitour, at least there is no outstanding use of ‘freeride’. Below are the numbers for ways, then relation in Opensnowmap rendering database.

pistes_imposm=# select count(*), difficulty from osm_pistes_ways where piste_type='skitour' group by difficulty;
 count |  difficulty  
-------+--------------
  2801 | 
   224 | advanced
   978 | easy
    92 | expert
    56 | extreme
   177 | freeride
   667 | intermediate
     4 | L
    41 | novice
     3 | WS
     1 | WS-
(11 lignes)

pistes_imposm=# select count(*), difficulty from osm_pistes_routes where piste_type='skitour' group by difficulty;
 count |  difficulty  
-------+--------------
     2 | novice
    53 | easy
    43 | intermediate
    16 | advanced
   451 | 
     5 | expert

Fritzifuchs · 2022-11-21T10:14:21.042Z

So I have the definition that for “Downhill” the difficulty “Freeride” simply means off-piste and does not actually contain a rating. For “Ski Tour”, the difficulty “Freeride” is actually the sixth most difficult level. Then that’s okay for me.

I would have one more remark: Since “downhill” with “freeride” always means unprepared slope, it should also be mapped with “backcountry”. However, this has the consequence that it is displayed in the OpenSnowMap with circles and is difficult to distinguish from a “ski tour” of difficulty level 6. (Only recognizable by the weak “shadow connection”).

This could be reconsidered. I don’t really want to do any “mapping for the renderer” and simply omit the grooming. There is the problem that backcountry uses the representation that is generally applied for ski tour.

Snap31125×797 127 KB

yvecai · 2022-11-21T17:40:37.056Z

There is certainly improvement to be done on Opensnowmap rendering, this is the reason its author started this post Confusion between differently tagged pistes rendered the same as circles is because, … I am confused !

To your knowledge what’s the difference on the ground between the R22 and R45 pistes in the screenshot ?