Calculates the angle between two lines, the angle between two planes, the
line of intersection of two planes, or the plane containing two apparent
dips, depending on the value of ans0.
Arguments
- trd1
Numeric. Trend of the first line, or strike of the first plane (radians, right-hand rule for planes).
- plg1
Numeric. Plunge of the first line, or dip of the first plane (radians).
- trd2
Numeric. Trend of the second line, or strike of the second plane (radians).
- plg2
Numeric. Plunge of the second line, or dip of the second plane (radians).
- ans0
Character. Operation selector:
"l"Angle between two lines (trend/plunge input).
"p"Angle between two planes (strike/dip input, right-hand rule).
"i"Trend and plunge of the intersection line of two planes.
"a"Strike and dip of the plane containing two apparent dips.
Value
A named list with components ans1 and ans2. For "l" and
"p", these are the angle and its supplement (degrees). For "i" and
"a", these are the trend/strike and plunge/dip of the resulting line or
plane (degrees).
References
Allmendinger, R. W., Cardozo, N., & Fisher, D. M. (2012). Structural geology algorithms: Vectors and tensors. Cambridge university press.
See also
Other structural algorithms:
CartToSphD(),
GreatCircleD(),
Pole(),
Rotate(),
SmallCircleD(),
SphToCartD(),
StCoordLineD(),
StPointD()
Examples
# Angle between two lines
Angles(trd1 = 3 * pi / 180, plg1 = 20 * pi / 180,
trd2 = 80 * pi / 180, plg2 = 40 * pi / 180,
ans0 = "l")
#> $ans1
#> [1] 1.388441
#>
#> $ans2
#> [1] 178.6116
#>
# Intersection of two planes
Angles(trd1 = 40 * pi / 180, plg1 = 30 * pi / 180,
trd2 = 120 * pi / 180, plg2 = 50 * pi / 180,
ans0 = "i")
#> $ans1
#> trd
#> 4.186462
#>
#> $ans2
#> plg
#> 0.03185937
#>