Orientation of structures from drill core orientation angles

Calculates the orientation of a plane or line from internal core angles ( alpha, beta, and gamma) of oriented drill cores

Usage

drillcore_orientation(azi, inc, alpha, beta, gamma = NULL)

Arguments

azi: numeric. Azimuth of drill core axis orientation in degrees (measured clockwise from North).
inc: numeric. Inclination of drill core axis in degrees (Note: negative values for downward).
alpha: numeric vector. Alpha angle in degrees
beta: numeric vector. Beta angle in degrees
gamma: numeric. (optional) Gamma angle in degrees

Value

object of class "Plane". If gamma is specified, "Line" object is returned.

Examples

# examples from Roger Marjoribanks (2016); 
# http://rogermarjoribanks.info/wp-content/uploads/2016/03/Plotting-alpha-to-locate-P.jpg
azi <- 225
inc <- -45

# single alpha-beta measurement
drillcore_orientation(azi, inc, 60, 320)
#> Plane object (n = 1):
#> dip_direction           dip 
#>      25.00392      70.02959 
drillcore_orientation(azi, inc, 45, 220)
#> Plane object (n = 1):
#> dip_direction           dip 
#>     333.24890      34.77544 

# multiple alpha-beta measurements
my_alphas <- c(60, 45)
my_betas <- c(320, 220)
res <- drillcore_orientation(azi, inc, alpha = my_alphas, beta = my_betas)


# Plot core-axis, and planes in stereonet
plot(Line(azi, -inc), lab = "core-axis")
points(res, col = 2:3)
lines(res, col = 2:3)
text(res, labels = c("A", "B"), col = 2:3, pos = 4)

# gamma measurements
my_gammas <- c(0, -10)
res2 <- drillcore_orientation(azi, inc, alpha = my_alphas, beta = my_betas, gamma = my_gammas)
points(res2, col = 2:3)