Linear interpolation of a y value at level xlev based on a vector x and y
LinInterp(x, y, xlev, ascending = FALSE, zeroint = FALSE)
A vector of x values
A vector of y values (identical length to x)
A the target level of x from which to guess y. Can be either a numeric or vector.
Are the the x values supposed to be ordered before interpolation
is there a zero-zero x-y intercept?
T. Carruthers
As of version 3.2, this function uses stats::approx