Use approx() to Return a Modifier Value From an RcA or RcT Curve
Value
A numeric value for modifying a growth curve in seir.
Note
This is a faster (and more simple) function that does what the original
cropsim afgen()
does.
The original implementation of this function comes from ZeBook and was adapted for use in epicrop by Adam H. Sparks.
Author
Adam H. Sparks, adamhsparks@gmail.com