I'm a mere Architect, with insufficient understanding of Civil Engineering, which may be why I'm having a hard time understanding what you're asking. For example, here:
the blue arrowhead is the start point, and the lower green path is your supposedly 20%-slope route. I drew the red paralleling it through a stretch that is essentially level, and then where my orange parallels it, the slope is suddenly and significantly steeper. So that path varies enormously in slope just within itself. What does 20% mean in that case? Can you describe in greater detail how that route was arrived at, and what's really intended?
Also, are the contours in 3D, that is, does each have its own real elevation in the Z direction, or is it a flattened 2D representation?
@libarraSCXGZ wrote:
.... if within a section the slope could vary greatly but always under 20% in this case or the percentage assigned to the routin[g]. .....
Yes, I understand what 20% represents. What I don't understand is how the routing that's labeled 20% was arrived at. The one labeled 30% looks like it would also be well under 20% in the beginning. [It's hard to say, not knowing what the contour interval is, nor the scale of the contour drawing.] So, for example, why does the 20% path not take the same route as the 30% path at least near the start where it's apparently under 20%? These are the kinds of considerations that make such a thing difficult to automate. Specific criteria on which to base calculations are necessary.
