geophys (version 1.4-1)

lipper: Ellipse calculator

Description

Return parametric version of ellipse from equation of an ellipse.

Usage

lipper(a, b, c, d = 0, f = 0, g = -1)

Arguments

a

numeric

b

numeric

c

numeric

d

numeric

f

numeric

g

numeric

Value

vector=c(ap, bp, phi)

Details

General quadratic equation is, \(a x^2 + 2 b x y + c y^2 + 2 d x + 2 f y + g = 0\)

References

<http://mathworld.wolfram.com/Ellipse.html>

Examples

# NOT RUN {
LIP = lipper(10, 3, 9)

theta  = seq(from=0, to=2*pi, length=360)

        phi = LIP[3]
        px = LIP[1]*cos(theta)*cos(phi)-  LIP[2]*sin(theta)*sin(phi)
        py = LIP[1]*cos(theta)*sin(phi) + LIP[2]*sin(theta)*cos(phi)


plot(px, py, type='p', asp=1)
lines(px, py)


# }