Rotate a line about an axis

Rotates a line (or axis) by applying a coordinate transformation matrix computed from the rotation axis and rotation magnitude. Based on the algorithm originally written by Randall A. Marrett.

Usage

Rotate(raz, rdip, rot, trd, plg, ans0)

Arguments

raz

Numeric. Trend of the rotation axis in radians.

rdip

Numeric. Plunge of the rotation axis in radians.

rot

Numeric. Rotation magnitude in radians (positive = right-hand rule about the axis).

trd

Numeric. Trend of the line to rotate in radians.

plg

Numeric. Plunge of the line to rotate in radians.

ans0

Character. "a" if the line to rotate is an axis (result forced into lower hemisphere); "v" if it is a vector.

Value

A named numeric vector c(trd, plg) with the trend and plunge of the rotated line in radians.

References

Allmendinger, R. W., Cardozo, N., & Fisher, D. M. (2012). Structural geology algorithms: Vectors and tensors. Cambridge university press.

See also

Other structural algorithms: Angles(), CartToSphD(), GreatCircleD(), Pole(), SmallCircleD(), SphToCartD(), StCoordLineD(), StPointD()

Examples

Rotate(raz = pi / 2, rdip = 0, rot = pi / 4,
       trd = pi / 4, plg = pi / 6, ans0 = "a")
#>        trd        plg 
#> 3.80310999 0.07954316