Hey, I would like the following features/operations regarding curves to be implemented.

Derivative curve
: It would be really helpful if we could get the derivative (or a granular slope value) from a given curve. This would allow for nice automation regarding the widths of a river, for example: Becoming wider near turns (high slope) and becoming thinner when the river is near straight. 
Absolute curve
: Kind of like the inverse curve, except it will only invert negative values. This will ensure a curve will always have a positive value, though it can lead to some strange results/kinks in the curve when it flips negative to positive. 
Normalise curve (between)
: Just like the normalise action of the clamp device, taking the the section of the curve and ensuring the highest value is x and lowest value is y. Since curves can go negative, I think it is best to let the user decide the values of x and y.