Feature #1850: Add Overlay mtb:scale

[ravenfeld]

Further to this PR, I would like to submit this PR which adds an overlay for the mtb:scale

#5308

This also follows on from the discussion here
fixes #1850
Helium314#559

I think the icon and icons need to be reviewed for better visibility, if the community can help with this that would be great.

I wanted to make sure I had the description because it can be complicated but the dialogue doesn't help. I can't force it to 100% width.

[westnordost]

Cool!

My first thought is however that this seems to be a kind of information that is a better fit for SCEE, as I am quite skeptical if it is possible to make the pictures and descriptions short but still clear enough that they can be answered by non-experts, i.e. non-(mountain)-byciclists. But we can try, of course, for any improvement here will also benefit if it is added to SCEE instead.

A partial /quick review:

[westnordost]

For consistency, the the title, description, image, ... should be put into extension functions in a separate file, to clearly separate the data from the resources. See e.g. SurfaceItem.kt

[ravenfeld]

Don't worry, it was to improve readability and performance on my side, but I'll modify it for you without any worries.

[westnordost]

A lot of code here and in that ViewController. Why can this not inherit from AImageSelectOverlayForm like the WayLitForm?

[westnordost]

Better images are a hard requirement. Minimum resolution is 384x384 px

[westnordost]

All descriptions are far too long. Also, tag values should not be mentioned. They must be understandable for non-experts.

[ravenfeld]

As I'm not good at English, I preferred to take what was in the wiki.
For the value, no worries, did the values indicated in the old PR seem right to you?

[ravenfeld]

Cool!

My first thought is however that this seems to be a kind of information that is a better fit for SCEE, as I am quite skeptical if it is possible to make the pictures and descriptions short but still clear enough that they can be answered by non-experts, i.e. non-(mountain)-byciclists. But we can try, of course, for any improvement here will also benefit if it is added to SCEE instead.

A partial /quick review:

I'm sorry, I didn't understand. You don't want this PR? There's no problem, this one can go into SCEE, it's just that as there was an open ISSUE and a former PR, we assumed that it would be of interest to you.

[westnordost]

You don't want this PR?

I wrote, that I am skeptical if the quest/overlay guidelines can be satisfied. In the current state of the PR, they are not. But maybe the PR can be enhanced.

My primary concern are the pictures in bad resolution and the very long description texts. If these texts cannot be shrunk to a fraction of the current text length without losing information important for their distinction, then it wouldn't satisfy the guidelines.

👨‍💻 Users are no experts: No knowledge about OpenStreetMap or any other background knowledge must be necessary
🐿️ Easy answer: Users are out and about and impatient. A quick, straightforward and clear answer must be possible

[westnordost]

Regarding wording, I think indeed some guidelines could be taken from the discussion there. For example, skill is subjective, doesn't make sense to mention it at all.

[ravenfeld]

Ok, I'll let the contributors who wanted this feature help me formulate it. I'd be happy to modify the code without any worries.

[mnalis]

mention @torhovland @westis @RubenKelevra @CloCkWeRX @cperrier @jonpsp @rhhsm @mcliquid - who seem to have had interest in mtb:scale quest for StreetComplete previously; perhaps they'd like to help with shorter descriptions for mtb:scale overlay?

[RubenKelevra]

@mnalis sure:
ravenfeld#1

[ravenfeld]

@RubenKelevra
Can you tell me that I'm deleting the word grade from the title and using what @torhovland had proposed?

    <string name="overlay_mtbScale_zero">No special skills needed</string>
    <string name="overlay_mtbScale_one">Obstacles can be ridden over</string>
    <string name="overlay_mtbScale_two">Requires some advanced riding skills</string>
    <string name="overlay_mtbScale_three">Concentration and very good skills needed</string>
    <string name="overlay_mtbScale_four">Some trials techniques will be necessary</string>
    <string name="overlay_mtbScale_five">Very few can ride here</string>
    <string name="overlay_mtbScale_size">Not rideable at all</string>

[westnordost]

In my opinion, it doesn't make sense to have these titles at all. What is "grade 2"? Apparently, that scala is based on the "Singletrail-Skala", a standard for MTB classification used in Germany and Austria. Unclear if it has any relevance beyond that. So, also unclear if even MTB (German-speaking) enthusiasts would know that "grade 2" is equal to "Schwierigkeitsgrad 2 auf der Singletrail-Skala".

We don't show the name of smoothness (e.g. "good", "intermediate" etc.) and we don't show the tracktype value as titles, so I would prefer to have one more line for a concise description than for a nondescript "grade X".

Unless that scale is really known beyond (some) German MTB enthusiasts. I can't judge that at the moment.

[westnordost]

This website has also some very concise descriptions for the different grades of the STS - in German:

https://thecycleverse.com/de/blog/singletrail-skala

Skala S0	Skala S1	Skala S2	Skala S3	Skala S4	Skala S5
Sehr leicht	Leicht	Mittel	Schwer	Sehr schwer.	Richtig schwer.
Fester und griffiger Untergrund, keine Hindernisse.	Loserer Untergrund möglich, kleine Wurzeln und Steine.	Untergrund meist nicht verfestigt, größere Wurzeln und Steine.	Verblockt, viele große Wurzeln oder Felsen, rutschiger Untergrund, loses Geröll.	Ösenartige Spitzkehren, Steilrampen, kaum fahrbare Absätze.	Gegenanstiege, der Weg ist eher ein Wandersteig, Spitzkehren mit Hindernissen.

[westnordost]

Also, very interesting information here! Turns out, there are international standard(s). I only read it vertically, but at least with the ITRS there might be a 1:1 equivalence, meaning that it might make sense to place the symbols there for better association and/or make this country-dependent which symbols are shown.

https://ride-with-love.bike/singletrail-skala/#welche_mountainbike_bewertungssysteme_gibt_es_und_wie_funktionieren_sie

[westnordost]

See also https://wiki.openstreetmap.org/wiki/Key%3Amtb%3Ascale%3Aimba

[ravenfeld]

See also https://wiki.openstreetmap.org/wiki/Key%3Amtb%3Ascale%3Aimba

It's not the same thing, at least in France.

the mtb:scale is used on all the paths where you practice mountain biking and the mtb:scale:imba is for the stations.
You can compare this with the colours for ski slopes and the mtb:scale the difficulty for ski touring.

[westnordost]

Is it like signed vs unsigned (e.g. maxheight vs maxheight:physical) or is the scale also different? E.g. mtb:scale=3 would rather bemtb:scale:imba=4 or whatever? You would say that displaying the icons alongside the pics would rather be harmful than helpful? My thinking is that MTBlers might generally know IMBA and how difficult each of these are. El 11 de julio de 2024 6:46:46 CEST, Alexis Lecanu ***@***.***> escribió:

…

> See also https://wiki.openstreetmap.org/wiki/Key%3Amtb%3Ascale%3Aimba It's not the same thing, at least in France. the mtb:scale is used on all the paths where you practice mountain biking and the mtb:scale:imba is for the stations. You can compare this with the colours for ski slopes and the mtb:scale the difficulty for ski touring. -- Reply to this email directly or view it on GitHub: #5726 (comment) You are receiving this because you commented. Message ID: ***@***.***>

[ravenfeld]

So basically it's a mix of enduro and downhill mtb difficulties. At least that's what's been done in France.

imba = downhill, in resorts with facilities.
mbt:scale = difficulty without layout, it's more for country and enduro.

[westnordost]

Yes, sure. mtb:scale:imba is used for mtb facilities that are dedicated and signed as such.

My point is this: MTB enthusiasts that want to map in streetcomplete the MTB scale of trails might know about the IMBA or ITRS scale and thus have developed a feeling which IMBA grade relates to which difficulty.
So, if an icon of the appropriate IMBA-classification would be displayed next to each selection option in a similar manner as it is done for the smoothness quest, it could help them choose the right option.

Do you think this would be helpful? Or do you think this would be confusing? (And with you I mean "you people interested in MTB mapping", not only @ravenfeld alone)

See also https://www.trailforks.com/map/legend/

IMBA seems to be used in US and/or internationally(?), UK/Euro is the ITRS standard.

[RubenKelevra]

My point is this: MTB enthusiasts that want to map in streetcomplete the MTB scale of trails might know about the IMBA or ITRS scale and thus have developed a feeling which IMBA grade relates to which difficulty.
So, if an icon of the appropriate IMBA-classification would be displayed next to each selection option in a similar manner as it is done for the smoothness quest, it could help them choose the right option.

I'm riding MTB for fun all my life but have no idea what IMBA/ITRS classifications mean.

It's like you love hiking and don't know how alpine trails are marked. 🤷‍♂️

[RubenKelevra]

@westnordost wrote:

This website has also some very concise descriptions for the different grades of the STS - in German:

https://thecycleverse.com/de/blog/singletrail-skala
Skala S0 Skala S1 Skala S2 Skala S3 Skala S4 Skala S5
Sehr leicht Leicht Mittel Schwer Sehr schwer. Richtig schwer.
Fester und griffiger Untergrund, keine Hindernisse. Loserer Untergrund möglich, kleine Wurzeln und Steine. Untergrund meist nicht verfestigt, größere Wurzeln und Steine. Verblockt, viele große Wurzeln oder Felsen, rutschiger Untergrund, loses Geröll. Ösenartige Spitzkehren, Steilrampen, kaum fahrbare Absätze. Gegenanstiege, der Weg ist eher ein Wandersteig, Spitzkehren mit Hindernissen.

Those descriptions are very good. I've merged those non-explicit surface details into our descriptions, to not overlap with the surface quest and thus not confuse the users:

ravenfeld#2

It's now:

0 - Firm and grippy ground. No obstacles, wide curves, moderate slope.
1 - Possible loose ground, small obstacles like roots and stones, or tight turns.
2 - Ground mostly not firm, large rocks and steps, wide hairpin turns, steepness up to 70%.
3 - Possible blocks, many large roots or rocks, slippery surface, many hairpin turns.
4 - Very steep with large boulders, roots, or tight hairpin turns. High steps, loose debris.
5 - Very steep, counter ascents, the path is more of a hiking trail, big boulder fields, debris, or landslides. Hairpin turns with obstacles, fallen trees.
6 - Not rideable with MTB. Chains, metal rungs, unsecured alpine paths, >45° steepness.

[westnordost]

A native speaker should definitely look over this. Some things sound a bit weird (TBH also in German - what's "verblockt"?) and I am not sure if these would be common terms. I could comment on this text, but maybe I end up adding more mistakes to it instead.

A few comments about the content:

• is to give steepness in percent understood internationally (e.g. US)? Depending on the answer to that, it should be used consistently, i.e. either in degrees or in percent
• Text number five is very long. I notice that it is a bit topsy-turvy: first steepness is mentioned, then what it rather appears like, then obstacles, then hazards, more hazards, then more obstacles and an example of an obstacle. Might be a good idea to have a consistent order in all these texts and not go back and forth.
• I think the abbreviation MTB should not be used. Just write "Impassable on bike".

[RubenKelevra]

TBH also in German - what's "verblockt"?

It means non-rideable objects. Meaning, you have to lift your bike over them.

---

Agree with the rest.

I think we should remove "steepness" as a detail people should map here, as we got the incline tag for it. I think it should more be an overall (and possible) detail of the difficulty, than a hard fact users should use to decide on if it's 5 or 6 for example.

I gave it another shot. :)

0 - Firm and grippy ground, no obstacles, wide turns.
1 - Some loose ground, easily navigable obstacles like roots and stones, or tight turns.
2 - Mostly loose ground, moderate obstacles like larger roots and stones, or difficult turns.
3 - Slippery surface or loose scree, challenging obstacles like blocks, many large roots or rocks, or switchbacks.
4 - Numerous challenging and technical obstacles like tight switchbacks, steep ramps, barely rideable drops.
5 - Extremely steep terrain with highly technical sections and numerous severe obstacles.
6 - Dangerous and impassable terrain, not suitable for mountain biking.

Edit: fixed typo

[westnordost]

What do you mean with blocks? Boulders? Or road-blocks? Why is 1 loose ground but 2 is mostly loose ground? (Is loose ground good?)
"Technical obstacle", "technical sections" sounds like "technically an obstacle". In any case, does it really serve to help classify the trail? I think it is better to (if not already done) give examples. E.g. in 5 I'd prefer "severe obstacles, like fallen trees" over "technical sections ... [with] severe obstacles"

[RubenKelevra]

What do you mean with blocks? Boulders? Or road-blocks?

Road-blocks, like fallen trees or other obstacles you can't ride over. If you got a different term for this, I'm open for suggestions. I thought "blocks" would work as a translation for "verblockt".

Why is 1 loose ground but 2 is mostly loose ground? (Is loose ground good?

Woops there's a "some" missing ;)

"Technical obstacle", "technical sections" sounds like "technically an obstacle". In any case, does it really serve to help classify the trail? I think it is better to (if not already done) give examples. E.g. in 5 I'd prefer "severe obstacles, like fallen trees" over "technical sections ... [with] severe obstacles"

Nope, it's not "technically an obstacle" but "you need technique to overcome this obstacle".

The difficulty of obstacles or paths is often referred to as "technical difficulty" and there are "technical skill required".

See https://www.mtblivigno.eu/en/single-track-scale-sts

Edit:

I think it is better to (if not already done) give examples. E.g. in 5 I'd prefer "severe obstacles, like fallen trees" over "technical sections ... [with] severe obstacles"

I don't think so. It leads users to see no fallen trees and say "oh no, so it must be a 4 not a 5". While 4 may very well contain fallen trees, as well as a 5 may have no trees at all along the path.

The texts are also too short to explain all possible scenarios. If you look at the full descriptions of the page linked above, it's a mouth full to explain it fully.

[normaclyde]

1 - Some loose ground, easily navigable obstacles like roots and stones, or tight turns.
2 - Mostly loose ground, moderate obstacles like larger roots and stones, or difficult turns.

In the US at least, "tight turns" and "difficult turns" are often synonymous with "hairpin turns". The S1 and S2 descriptions mentions turns in the context of not having hairpin turns and narrow curves. If I am interpreting "narrow curves" correctly, another way to phrase S2 it is "narrow lines", meaning that sections of the trail, including gentler curves, require riders to follow an exact line.

Also, recommendation for S3 in alignment with the S grades:
3 - Slippery surface or loose scree, challenging obstacles like boulders, many large roots or rocks, steps, tricky traverses, or hairpin turns.

That language better gets the point across IMO.

[RubenKelevra]

@normaclyde right. I can see how one may confuse tight or difficult turns with hairpin turns.

I modified it:

0 - Firm and grippy ground, no obstacles, wide turns.
1 - Some loose ground, easily navigable obstacles like roots and stones, no hairpin turns.
2 - Mostly loose ground, moderate obstacles like larger roots and stones, steps, narrow curves.
3 - Slippery surface or loose scree, challenging obstacles like boulders, many large roots or rocks, steps, tricky traverses, hairpin turns.
4 - Numerous challenging and technical obstacles like tight switchbacks, steep ramps, barely rideable drops.
5 - Extremely steep terrain with highly technical sections and numerous severe obstacles.
6 - Dangerous and impassable terrain, not suitable for mountain biking.

[westnordost]

@normaclyde You are from the #trails or #language channel, right? Thanks for your input!

[westnordost]

So, the other thing that is missing are better representative images of sufficient resolution. Maybe it would make sense to open a request for contributions in the forums.

[RubenKelevra]

I'd take the S5 for the S6, because S5 certainly goes on the mountain bike

Ah yeah, that makes sense, how about putting another image in for S2 and moving the rest up?

S0:

Firm and grippy ground, no obstacles, wide turns.

Source

S1:

Some loose ground, easily navigable obstacles like roots and stones, no hairpin turns.

Source

S2:

Mostly loose ground, moderate obstacles like larger roots and stones, steps, narrow curves.

Source

S3:

Slippery surface or loose scree, challenging obstacles like boulders, many large roots or rocks, steps, tricky traverses, hairpin turns.

Source

S4:

Numerous challenging and technical obstacles like tight switchbacks, steep ramps, barely rideable drops.

Source

S5:

Extremely steep terrain with highly technical sections and numerous severe obstacles.

Source

S6:

Dangerous and impassable terrain, not suitable for mountain biking.

Source

Edit: I flipped S4/S5 to align better with the texts.

[RubenKelevra]

@normaclyde wrote:

Another possible S0 contributed by a friend:

Thanks, but the foreground with the trees looks a bit too busy IMHO

[westnordost]

I can't comment too much on whether the pictures are representative for the respective grade, so I'd leave this to people more into the MTB topic. Not sure if the MTB people know of this discussion. Maybe better on the forum?

Anyway, from the point of view of StreetComplete, I'd comment:

• What is important to show is primarily the trail, not the rider, bike or surrounding landscape or scenery
• The pictures still look a bit blurry and/or of not-that-good quality (e.g. S0, S1), but maybe that is just the downscaled version shown in this discussion

[torhovland]

As a mountain biker, I can confirm that the pictures are somewhat representative, but not quite good enough:

• S0 (compacted trail): Good.
• S1 (rider on a mountain): Not so good. The picture in the PR (with the roots) gives a better impression of the grade than this picture (which doesn't show the surface very well).
• S2 (riders on a rocky path): Fair, but this trail could have been S1 as well. The photo should show larger roots or stones, steps, or narrow curves.
• S3 (downhill racer out of the woods): Fair, but this could have been S2 as well. The photo should show more slippery surface, steps, tricky traverses, or hairpin turns, like the picture in the PR.
• S4 (downhill racer on sandy trail): This photo is not good. The terrain shown could just as easily have been S2/S3.
• S5 (downhill racer on rock surface): This photo is also not representative. The surface shown could have been S3.
• S6 (impassable terrain): Fair, but the photo doesn't show whether this is actually impassable downhill. The rock climb cliff in the PR is more representative.

[westnordost]

(If the current photos from the PR are deemed representative, another possibility could be to contact the original authors of the photos, asking whether they have the originals in higher resolution.)

[TommiContursi]

I appreciate the effort you put into adding the MTB scale feature. Being able to change the MTB scale of a trail directly while on the track is a fantastic addition. It’s great to see the community collaborating on this. However, I understand the challenges of trying to standardize these MTB scales globally, especially given the current state of confusion. I came across an insightful article on this topic that you may find interesting: https://www.singletracks.com/mtb-trails/why-cant-anyone-agree-on-mtb-trail-difficulty-ratings

We don't have mountains or many officially designated mountain biking trails in Finland. However, we have a vast expanse of wild nature full of paths/trails in a variety of terrains, such as pine forests, swamps, high cliffs, and more. These trails are free for anyone to use, no matter if you cycle or hike. I believe that this situation is quite similar in many other countries, which is why it would be beneficial if these mtb:scale descriptions could apply to as many countries as possible.

The descriptions and images should not be limited to mountainous regions and downhill-type biking. I fully agree that images should be about trails and not riders.

Here's how these mtb:scale tags are used in Finland by Trailmap app, which is an extremely popular OSM-based mountain biking app. These MTB scale descriptions are here in Finnish, but I do like how these describe trails for all types of users (serious MTB riders, gravel riders, regular cyclers and even trail runners).

At least, I do hope that Finnish users can use these Trailmap descriptions; otherwise, Finnish app users could mess up some existing trail difficulties.

Edit. Also good to note that mtb:scale alone is not always sufficient, and trail width, surface, and other Trailmap wiki listed and here commented tags would provide much more information for trail users.

---

Trailmap Difficulty Levels (Loosely translated):
Link: https://wiki.trailmap.fi/fi/kartoitus/tagit

mtb:scale=0- Very Easy Path: Smooth outdoor paths and forest roads, etc. Does not require any off-road skills and can be ridden with a city bike or road bike.

mtb:scale=0 Easy Path: Needle-covered path or similar smooth easy track, with few stones or roots. Does not require special off-road skills, pleasant even for beginners, and can be easily ridden with a cyclocross bike.

mtb:scale=1 Intermediate Path: Small stones or roots. Obstacles can mainly be crossed with a mountain bike without bypassing. Mostly easy to ride with basic skills on a mountain bike, but a beginner may occasionally need to dismount. Still rideable with a cyclocross bike for a skilled rider.

mtb:scale=2 Difficult Path: Larger stones and roots. There may be smaller drops. Requires concentration even from more experienced riders and is not easy for most, especially uphill and when wet. Cyclocross bike needs to be carried on the shoulder.

mtb:scale=3 Very Difficult Path: Many large stones, roots, and other obstacles. Large drops and challenging climbs. Almost impossible to ride uphill. Requires tight concentration from experienced riders and is slow to ride. Beginners often need to push their bikes frequently.

mtb:scale=4 Extremely Difficult Path: Extremely difficult due to large obstacles and height differences, requires exceptional trials-type skills to ride even very slowly. Very slow to run for trail runners as well.

mtb:scale=5 Almost Impossible Path: Practically unridable for almost everyone due to large obstacles, height differences, and winding paths. Theoretically rideable with sufficient skills.

mtb:scale=6 Unridable Path: Not rideable regardless of skills due to, for example, long vertical drops or large, densely located obstacles. Requires concentration even on foot.

[TapioKn]

In my opinion the latest set of images has way too big of a difference between S0 and S1. Even if S1 is technically easily navigable and has no turns, even just the way appearing to be fairly steep and along a ridge makes it look difficult and dangerous. In contrast S0 would be fine for a traditional road bike and would be more of a 0-. I think that it would be good to have some minor roots/rocks/unevenness even in the S0 image/description. Something that's not an obstacle as such and can be easily ridden over even with narrow tires, but shows that these don't have to be totally smooth. Otherwise anything that's not passable with roller blades ends up as ≥S1. Unfortunately I couldn't find such an image just now though.

I agree with TommiContursi that the images (or descriptions) shouldn't be focused on (built) downhill trails. Actually I would go so far as to say that those are the least important trails for mtb:scale, since they often already have some sort of marked difficulty, while regular forest trails etc. don't.

[RubenKelevra]

(If the current photos from the PR are deemed representative, another possibility could be to contact the original authors of the photos, asking whether they have the originals in higher resolution.)

Yeah that idea crossed my mind as well, as the pictures from the wiki are really hard to match up, as @torhovland pointed out.

[RubenKelevra]

@TommiContursi wrote:

At least, I do hope that Finnish users can use these Trailmap descriptions; otherwise, Finnish app users could mess up some existing trail difficulties.

is your concern aimed at the images or the descriptions?

Because the images were just a shot to get some responses on how to proceed and if we could replace some of the original images with higher resolution/quality ones - as it's unlikely that someone has access to all categories of tracks and can snap some pictures.

But you seem to have some tracks in mind with different categories.

Feel free to grab some pictures and let's discuss them!

[TommiContursi]

@TommiContursi wrote:

At least, I do hope that Finnish users can use these Trailmap descriptions; otherwise, Finnish app users could mess up some existing trail difficulties.

is your concern aimed at the images or the descriptions?

Because the images were just a shot to get some responses on how to proceed and if we could replace some of the original images with higher resolution/quality ones - as it's unlikely that someone has access to all categories of tracks and can snap some pictures.

But you seem to have some tracks in mind with different categories.

Feel free to grab some pictures and let's discuss them!

I am concerned about the descriptions and the images.

I just went cycling in my local forest and took photos of different trails, mainly with mtb:scale ratings of 0 (or even 0-), 1, 2, and maybe 3. I have added all these photos to a Google Photos folder, and they are available for use if you're interested.

https://photos.app.goo.gl/MFf5FB9AqKFiFcGa7

One challenge with the photos is that it's hard to take consistent pictures that capture all the trail features and that are easily comparable in the app. Perhaps, AI might be able to generate comparable images more easily. I have included a set of AI-generated pictures as an example. I'm not a big fan of this AI photo style, as many of these images don't look realistic and seem very AI-generated. The roots and other details are exaggerated. This is just to demonstrate what can be achieved in a short time. Getting better results would require more time and prompting. This approach would allow us to have consistent images from the exact location but with different trail difficulties.

[ravenfeld]

It could be a good idea, but the difficulty of the pins is missing, as you'll pass more easily when you're hanging straight.
So this PR is still blocked due to a lack of images? I'm not very good in English so I don't discuss things on the osm forum but only on the French one. Should we get more people involved?

[torhovland]

My two cents:

We should stick with the OSM Wiki images and get this merged. Then somebody should update the Wiki with better and higher resolution images. And then StreetComplete should be updated with the new Wiki images.

The AI images generated above is not a bad idea, even if they do look quite artificial. And they focus too much on roots. S3 and above should have other challenges than just bigger roots and rocks.

[TommiContursi]

My two cents:

We should stick with the OSM Wiki images and get this merged. Then somebody should update the Wiki with better and higher resolution images. And then StreetComplete should be updated with the new Wiki images.

The AI images generated above is not a bad idea, even if they do look quite artificial. And they focus too much on roots. S3 and above should have other challenges than just bigger roots and rocks.

I completely agree! It's best to start with the default images and possibly change them later. There's no need to delay this just because of that.

I want to emphasize that those AI images were generated in minutes. Achieving better results would require more time and better prompting. However, I still believe that using those images would be a good way to have comparable images. Another option would be to draw images or create them using Unreal Engine. Both are time-consuming and require skills.

[RubenKelevra]

My two cents:

We should stick with the OSM Wiki images and get this merged. Then somebody should update the Wiki with better and higher resolution images. And then StreetComplete should be updated with the new Wiki images.

The AI images generated above is not a bad idea, even if they do look quite artificial. And they focus too much on roots. S3 and above should have other challenges than just bigger roots and rocks.

I agree. I think that's the best way forward. The OSM wiki is what non SC users will use and have used for years. Those images represent what users are expecting of the trails.

[RubenKelevra]

My two cents:
We should stick with the OSM Wiki images and get this merged. Then somebody should update the Wiki with better and higher resolution images. And then StreetComplete should be updated with the new Wiki images.
The AI images generated above is not a bad idea, even if they do look quite artificial. And they focus too much on roots. S3 and above should have other challenges than just bigger roots and rocks.

I completely agree! It's best to start with the default images and possibly change them later. There's no need to delay this just because of that.

I want to emphasize that those AI images were generated in minutes. Achieving better results would require more time and better prompting. However, I still believe that using those images would be a good way to have comparable images. Another option would be to draw images or create them using Unreal Engine. Both are time-consuming and require skills.

Sure, all 3 options are valid, but I agree with @torhovland that those images should be discussed on the wiki page and replaced there. I think that's better.

It's also the approach SC is using for the surfaces.

[mnalis]

I agree. I think that's the best way forward. The OSM wiki is what non SC users will use and have used for years. Those images represent what users are expecting of the trails.

It should be noted however that:

• StreetComplete has certain quality standards, which tend to be set above that of average wiki OSM page, so traditional OSM tradeoffs like let's go with "meh" solution, as it can always be improved later are less likely to be acceptable
• StreetComplete targets specific category of the users who are not familiar with OSM at all (and must not be required to be knowledgeable about MTB to be able use the Quest/Overlay!) - which is not the case at all for OSM wiki.
• lower-quality pictures on the wiki might be more acceptable than in SC, because on wiki they are accompanied by extra links and very long and detailed texts which help to explain those pictures in details (while such links and long and detailed texts are not really an option for StreetComplete, where texts should be short in concise, which means the pictures must be better for comparable information to be transferred).

So, regarding pictures as noted in #5726 (comment), did someone took the effort to ask at https://community.openstreetmap.org/ ? If they did, could they link the discussion here?

[TommiContursi]

@mnalis I agree entirely with your points about maintaining high-quality standards for StreetComplete, especially since the app's target users aren't familiar with OSM or MTB specifics.

While images are important, having easily understandable text descriptions is even more crucial in my opinion, so I would like to reopen this can of worms. The proposed descriptions such as Grade 2: Large rocks and steps. Loose soil, wide hairpin turns, steepness up to 70%, Grade 3: Large boulders and roots, many hairpin turns. Slippery surface, and Grade 4: Very steep with large boulders, roots, or tight hairpin turns. High steps, loose debris are still too technical and require readers to analyze the path in detail to match the descriptions. These terms like "hairpin turns" and specific steepness percentages might be familiar to experienced riders or those with a background in cartography, but they can be confusing for others. Moreover, they are highly subjective. For one person, the same trail might be a Grade 4, while for another, it might be a Grade 2. The difficulty or size of obstacles is always relative to the user's skill level, so the options need to be as distinct and clear as possible. Without context about the rider’s capabilities, the descriptions lack clarity, making them difficult to apply consistently across different users.

The earlier proposed trailmap.fi descriptions are better as they use everyday language and clearly define obstacles and skill levels required. For example, Intermediate Path: Small stones or roots. Obstacles can mainly be crossed with a mountain bike without bypassing. Mostly easy to ride with basic skills on a mountain bike, but a beginner may occasionally need to dismount. Still rideable with a cyclocross bike for a skilled rider. This description is clearer and easier for users to quickly understand. Everyday language uses familiar terms and relatable scenarios, providing clear guidance on the necessary skills and equipment. This helps users assess both trail difficulty and the capabilities required of their bikes. While both technical and everyday descriptions mention skill levels, everyday language is more precise about the type of skills needed and how they relate to the rider's abilities and equipment. For example, noting that a trail is "still rideable with a cyclocross bike for a skilled rider" gives practical context, enabling riders to evaluate trails relative to their skills and equipment. And yes, I know those are currently very long, but those can be easily shortened without losing any important information.

Using everyday language provides several benefits: it allows riders of all experience levels to quickly grasp what to expect from a trail by specifying the skills and bike types needed. This clarity and easy-to-understand format enable riders to make quicker, more informed decisions about whether a trail matches their skill level and equipment, improving their overall experience. However, poor descriptions can lead to inaccurate MTB scale data, as users unfamiliar with the scale may rate paths inconsistently, potentially degrading the quality of the data over time.

I also agree with @TapioKn 's comment that the images (or descriptions) shouldn't focus on (built) downhill trails. These trails often already have marked difficulty levels, while regular forest trails do not. Emphasizing these regular trails is more important for the mtb:scale. StreetComplete's idea, to my understanding, is to get regular smartphone users to contribute to OpenStreetMap data from places where it is missing. Therefore, it makes no sense to focus on officially rated trails when our target is the everyday paths and trails that lack detailed assessments.

This is my two cents on the topic. While I hope the feature can be implemented quickly, I fully support your point that StreetComplete targets users who are not familiar with OSM and should not need MTB knowledge to use the Quest/Overlay.

[HolgerJeromin]

It's also the approach SC is using for the surfaces.

Nope.
SC authors searched high quality images for SC and put them into wiki, too.

[RubenKelevra]

It's also the approach SC is using for the surfaces.

Nope. SC authors searched high quality images for SC and put them into wiki, too.

I'm sorry but how exactly is your answer different than mine? 🤔

[RubenKelevra]

@mnalis wrote:

• StreetComplete has certain quality standards, which tend to be set above that of average wiki OSM page, so traditional OSM tradeoffs like let's go with "meh" solution, as it can always be improved later are less likely to be acceptable

I appreciate your feedback, but I believe it's a bit off the mark. We've dedicated several rounds to refining the texts for this quest. I suggested using images that have been the standard for rating difficulties for over a decade. In my opinion, these images are quite effective. The low resolution isn't a major issue since they are displayed small enough that it doesn't impact clarity.

• StreetComplete targets specific category of the users who are not familiar with OSM at all (and must not be required to be knowledgeable about MTB to be able use the Quest/Overlay!) - which is not the case at all for OSM wiki.

While StreetComplete aims for a low entry barrier, rating MTB difficulties requires specific mountain biking knowledge. A short text and an image can’t adequately educate users on this matter.

I disagree with the idea that users without MTB experience can accurately rate these difficulties. Without proper knowledge, they might input useless data, regardless of image quality. If someone has never ridden a mountain bike, they can't distinguish between easy and difficult obstacles and might rate everything as “scary.”

There should be a disclaimer when enabling this layer/quest, advising only those with mountain biking experience to make changes.

[RubenKelevra]

@TommiContursi wrote:

The earlier proposed trailmap.fi descriptions are better as they use everyday language and clearly define obstacles and skill levels required. For example, Intermediate Path: Small stones or roots. Obstacles can mainly be crossed with a mountain bike without bypassing. Mostly easy to ride with basic skills on a mountain bike, but a beginner may occasionally need to dismount. Still rideable with a cyclocross bike for a skilled rider. This description is clearer and easier for users to quickly understand. Everyday language uses familiar terms and relatable scenarios, providing clear guidance on the necessary skills and equipment. This helps users assess both trail difficulty and the capabilities required of their bikes. While both technical and everyday descriptions mention skill levels, everyday language is more precise about the type of skills needed and how they relate to the rider's abilities and equipment.

I'm sorry, but @westnordost said that "skill level" and very long descriptions are not acceptable:

@westnordost wrote:

For example, skill is subjective, doesn't make sense to mention it at all.

@westnordost wrote:

All descriptions are far too long.

---

@TommiContursi wrote:

These terms like "hairpin turns" and specific steepness percentages might be familiar to experienced riders or those with a background in cartography, but they can be confusing for others.

Hairpin turns and steepness in percentages are used on street signs. So everyone with a driver license should readily understand those terms. So I would rate them as common knowledge and not requiring a background in cartography.

I also like to mention, that you used older descriptions which have been already modified. Here's the current version:

• Grade 0 - "Firm and grippy ground, no obstacles, wide turns."
• Grade 1 - "Some loose ground, easily navigable obstacles like roots and stones, no hairpin turns."
• Grade 2 - "Mostly loose ground, moderate obstacles like larger roots and stones, steps, narrow curves."
• Grade 3 - "Slippery surface or loose scree, challenging obstacles like boulders, many large roots or rocks, steps, tricky traverses, hairpin turns."
• Grade 4 - "Numerous challenging and technical obstacles like tight switchbacks, steep ramps, barely rideable drops."
• Grade 5 - "Extremely steep terrain with highly technical sections and numerous severe obstacles."
• Grade 6 - "Dangerous and impassable terrain, not suitable for mountain biking."

[HolgerJeromin]

I'm sorry but how exactly is your answer different than mine? 🤔

I interpreted your text as:
"SC can use lower quality images now and in the future some wiki users will (hopefully) provide better images."
I wanted to emphasis that with surfaces the drive for very good images was from SC devs in order to make the quest reality.

But perhaps I interpreted your text wrong.

[RubenKelevra]

@HolgerJeromin What I mean is that we should update the wiki with these images before SC switches to different ones. And also make sure that this change is discussed and accepted by the community. The wiki has documented this tag for 15 years, and everyone who has tagged or used the tag likely viewed these images as reference.

I also don't think their quality is bad. They were never meant to be viewed full screen. If you check the screenshot in the first post, they are actually downscaled.

These images effectively convey what each grade represents, and that's what really matters.

So I don't see no blocker in going forward with these images, as they are fine conveying what they are supposed to convey.

[TommiContursi]

Thank you, @RubenKelevra for sharing the updated descriptions. I appreciate the effort put into making them clearer and more user-friendly. In previous discussions, you considered dropping the term “Grade” as it may not add much value. So, I propose dropping it and instead using descriptors like “Easy” to “Unridable” to complement your existing descriptions. This approach provides intuitive cues about the trail’s nature without implying a required skill level.

These initial descriptors, such as “Easy” or “Difficult,” are not meant to indicate the rider’s skill level but to provide a verbal summary of the trail’s challenges. They describe the physical characteristics of the trail itself, offering an immediate understanding of what to expect. This is particularly useful for users unfamiliar with technical MTB terminology. By focusing on the trail’s objective features, these descriptors help users make consistent assessments, supporting the accuracy and reliability of the data collected.

Additionally, without clear verbal descriptions, there is a risk that users might incorrectly apply the full scale to relatively simple trails. In places like Finland, where natural trails rarely reach the higher difficulty levels of 4-6, using clear descriptors can help prevent this kind of misapplication and ensure data consistency.

Here’s how your descriptions could be complemented with these initial terms:

• 0 - Easy Path: Firm and grippy ground, no obstacles, wide turns.
• 1 - Intermediate Path: Some loose ground, easily navigable obstacles like roots and stones, no hairpin turns.
• 2 - Difficult Path: Mostly loose ground, moderate obstacles like larger roots and stones, steps, narrow curves.
• 3 - Very Difficult Path: Slippery surface or loose scree, challenging obstacles like boulders, many large roots or rocks, steps, tricky traverses, hairpin turns.
• 4 - Extremely Difficult Path: Numerous challenging and technical obstacles like tight switchbacks, steep ramps, barely rideable drops.
• 5 - Almost Impossible Path: Extremely steep terrain with highly technical sections and numerous severe obstacles.
• 6 - Unridable Path: Dangerous and impassable terrain, not suitable for mountain biking.

I hope these suggestions are helpful and that the descriptions continue to be refined for usability, ensuring they remain easy and quick to interpret for all users.

[ravenfeld]

Hello, I would like to propose or not the mtb_scale or quest overlay to users. Does this seem possible on SC or should I do the code on SCEE as I had planned at the beginning?

[westnordost]

Uh, I haven't been following this lately, but it looks like with the help of @RubenKelevra and others, a good wording has already been found. So it looks like the only thing which is missing still since I last had a look at this PR are representative pictures in adequate resolution and quality.

If you and noone else interested in this feature is able to find such pictures (but really, representative and not blurry in 384x384px is not a huge requirement, or is it?), then, well, sure you can give it a try to pose this PR to SCEE, maybe its maintainer cares less about this than I.

Edit: Also, if the current texts continue to take more vertical space than a (square) picture would, it would be completely okay if the pictures had another aspect ratio, i.e. be less wide.

[westnordost]

Since Ruben has been playing around with AI a bit, and if really no other pictures can be found that what we currently have, maybe they could be upscaled with AI? I am often quite shocked by how good the results of such things are. After all, in terms of resolution in order to not be blurry, there isn't missing much.

Edit:
Well, about 3x... my god, are the current pictures bad. The unscaled variant that is only 180px in width already looks blurry/upscaled. Maybe it is just really bad JPEG quality. Marks of the early internet.

By the way, I do care about this PR. For example, I actually contacted the people from www.singletrail_skala.de from which these pictures are taken, whether they still have unscaled pictures. No reply though. This website seems pretty dead. (Which raises the question whether it makes sense to classify MTB trails according to this scala, but well 🤷‍♂️, I guess by now mtb:scale has rather become somewhat of the "OSM MTB Scale" than the "Singletrail Skala")

[ravenfeld]

I understand. I used the images from the wiki. I thought it spoke to more people but I told myself that they are people who know the wiki.
I am interested in new images so that I can modify the PR without worry. For my part, I have been contributing with this overlay in the app for several months, so whether it progresses or not is more for the community.