SAC scale should remain to be tagged on trails in parts of the world where it is regularly used and in common use by the community. As I noted above, the SAC scale compounds several different aspects of route difficulty (slope, surface, route-finding/visibility, fall risk/exposure) and foot_scale= only covers one aspect (difficulty of movement) and is independent of the others.
foot_scale is likely most useful outside of the areas of the world where SAC is commonly used, but could be helpfully applied in the Alpine/European context to provide additional information on what to expect even if a SAC value us known. Using both trail_visibility and foot_scale can confirm with more precision and some of the components that go into a SAC rating as trail with easy movement and poor visibility might get the same SAC rating as a similar one with good visibility and more difficult movement.
The key foot_scalehasn’t troubled the scorers yet. If it gains acceptance and represents anything useful with a data consumer hat on I’d happily consume yet (like I do now for highway=scramble and scramble=yes). I just suspect that it’s even less likely to gain acceptance than those two.
Thanks for the clarification. Now, for some details.
Correct. The so-called “difficulty”.
That is practically very easy. If you take the element with the highest value, then it represents the highest value for the whole section, even if the other elements are pretty low on the scale.
See, that’s already T3, no matter if there are easy sections. Even when you do a multi-pitch climbs of level V, let’s say, you do come across terraces where you can stand comfortably or walk a few meters. The overall route is still grade V because you’re not going to land on that section with a helicopter.
As I wrote, exactly what the SAC scale was supposed to do. Arguably, for mountain hiking. So, yes, it was never designed for urban paths. In that sense they are all T1. Just look at the description from the OSM wiki:
“Trail well cleared. Exposed areas well secured.
Terrain level or slightly inclined; no risk of falling with appropriate behaviour.
Requirements: None, Can be hiked in ordinary sports shoes/trainers, Orientation straightforward, even without a map”
I still see a lot of overlap, because the purpose is exactly the same - expressing difficulty of the path. That’s why there are multiple elements. It’s not a Bible, to be held to the word, but it describes difficulty in terms of elements experienced on such paths, generalized in order to classify them.
This really reminds me of xkcd: Standards
Except that those elements represent the difficulty of movement. I’ve been on Via Ferratas with people who get literally paralyzed by the exposure. The rest of the group hops on the rocks effortlessly. How “difficult” is that terrain?
An older person on a hike has a problem crossing a 15cm stone. The rest of the group hops over it without thinking. How difficult is that section?
I could go on for every aspect mentioned in the SAC description. I’m not a fanboy of the SAC scale but am wondering what is essentially different between the two. And I’m not particularly convinced by the arguments so far.
This is fine, foot_scale= as it stands is designed to be somewhat independent of the highway= classification. There’s no rule of the form, if it has a foot_scale= value, then it must be a highway=path. So if eventually highway=scramble is approved, we can change the highway= value of those ways, without changing the foot_scale= value.
@mods-general This topic featured some insightful comments today. But this topic has been superseded. I opened that when I took on interim development of key foot_scale. The prime mover took office again here. – Please close this topic from further commenting.