Orientation of structures from drill core orientation angles
Source:R/alphabeta.R
drillcore_orientation.Rd
Calculates the orientation of a plane or line from internal core angles ( alpha, beta, and gamma) of oriented drill cores
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
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)