This returns the eccentricity given the third flattening (n).
Examples:
Scalar input:
n_earth = 0.0016792; ecc_earth = n2ecc (n_earth) => ecc_earth = 0.081819
Vector input:
n_vec = [ 0.0016792 0.033525 ]; ecc = n2ecc (n_vec) => ecc = 0.081819 0.35432
See also: n2ecc.
Package: mapping