If the center is open white assume it has a forest on top of it. If it is filled in black then it is anything from bare rock to ferns and low brush.
For the most part, you can get to the top of the boulders so there isn't a reason to map if it is runnable.
That’s kind of what I thought, but I couldn’t always make that match in my head. Based on how the Nav was going, it’s quite possible I was looking at the wrong boulders tho!
I found the mapping to be annoying accurate. If you look around the map there are much tougher areas of boulders for navigation.
The rare double stacks are very odd, a 10m boulder sitting on top of a 10 meter boulder. Then there are trees growing on both of them. How do you make that?