Which is the difference between a RED trail and a BLACK trail? Also, there are one diamond black trails and just Black trails, without any diamond, which is the difference between them?
well there are different trail grade systems. Most the world uses IMBA grades, but UK, and a lot of europe uses a different system. New Zealand has yet another system.
I need to create a more detailed map legend page on the website.
Thing is that when you add a trail you don't have the RED dificult level available, you just got: Access Road/Trail Easiest / White Circle Easy / Green Circle Intermediate / Blue Square Very Difficult / Black Diamond Extremely Difficult / Dbl Black Diamond Extremely dangerous, pros only!
But if, for example, I try to edit this trail (https://www.trailforks.com/trails/view-49446/) with red difficulty rating then the red option is available at the end of the previous difficulty level list.
That's why I'm asking, should I leave that red level or edit and make it one diamond black level in order to go with current Trailforks difficulty rating system?
It all depends on what is the local custom. If the region doesn't use red triangle as a rating, then by all means change it.
But the UK and many other areas of europe do use it. Trailforks is meant to be flexible to cater to the local standards. If there isn't a local standard, I recommend the Trailforks/IMBA default then.
But that's my point, there is no RED difficulty level when adding a trail, just the ones I posted. I understand that each region has it's standard and Trailforks should be as accurrate as possible. But then when editing a trail, any trail, any region, should show the same list of difficulty levels. If not, is confusing, from the user point of view. Don't know if I'm explaining my self correct, hope yes.
When adding or editing a trail, the difficulty options a shown depend on what the parent regions default is set too. So if the correct options are not shown, then the region your adding the trail too, needs to be edited to use the correct difficulty rating system first.