def line_above_plane(strike, dip, lplunge, lbearing):
"""
Evaluates if line is above a plane (great circle), such that
1) the line has a smaller plunge compared to that of its vertical projection
onto the plane (as rake), and 2) it has the same bearing as that of the rake.
Parameters
----------
strike : int or float
The strike of the plane in degrees, with dip direction indicated by
the azimuth (e.g. 315 vs. 135) specified following the "right hand
rule".
dip : int or float
The dip of the plane in degrees.
lplunge, lbearing: integer or float
plunge, bearing of a line
Returns
-------
aboveplane*samebearing: boolean
True if line is above the plane
"""
# project line to plane as rake
rake_angle = st.azimuth2rake(strike, dip, lbearing)
# convert rake to line defined by plunge and bearing
rlon, rlat = st.rake(strike, dip, rake_angle)
rplunge, rbearing = st.geographic2plunge_bearing(rlon, rlat)
# evaluate if line is above the rake
smallerplunge = rplunge > lplunge
# evaluate if line has the same bearing as the rake
samebearing = np.abs(rbearing - lbearing) < 0.001
return smallerplunge * samebearing
def tangent_lineation_plot(ax, strikes, dips, rakes):
"""Makes a tangent lineation plot for normal faults with the given strikes,
dips, and rakes."""
# Calculate the position of the rake of the lineations, but don't plot yet
rake_x, rake_y = mplstereonet.rake(strikes, dips, rakes)
# Calculate the direction the arrows should point
# These are all normal faults, so the arrows point away from the center
# Because we're plotting at the pole location, however, we need to flip this
# from what we plotted with the "ball of string" plot.
mag = np.hypot(rake_x, rake_y)
u, v = -rake_x / mag, -rake_y / mag
# Calculate the position of the poles
pole_x, pole_y = mplstereonet.pole(strikes, dips)
# Plot the arrows centered on the pole locations...
arrows = ax.quiver(pole_x,
pole_y,
u,
v,
width=1,
headwidth=4,
units='dots',
pivot='middle')
return arrows
def plot_polarities(self,
ax=None,
show: bool = False,
label: bool = True) -> plt.Axes:
if not ax:
fig = plt.figure()
ax = fig.add_subplot(111, projection="stereonet")
for polarity in self.polarities:
toa, baz = polarity.toa, polarity.azimuth
assert 0 <= toa <= 180, f"Take off angle ({toa}) does not lie between 0 and 180"
if 0. <= toa < 90.:
toa = 90. - toa # complement for downward angles
elif 90. <= toa <= 180.:
toa = 270. - toa # project upward angles
baz -= 90 # Calculate strike azi from direct (dip-pointing) azi
if polarity.polarity in UPS:
plot_kwargs = POLARITY_PROPS["up"]
elif polarity.polarity in DOWNS:
plot_kwargs = POLARITY_PROPS["down"]
else:
plot_kwargs = POLARITY_PROPS["unknown"]
# Ensure boundedness
baz = baz % 360
ax.rake(baz, toa, 90, **plot_kwargs)
if label:
lon, lat = mplstereonet.rake(baz, toa, 90)
ax.text(lon[0], lat[0], polarity.station)
plot_kwargs.pop("label", None) # Only label once
if show:
plt.show(block=True)
return ax
def fault_and_striae_plot(ax, strikes, dips, rakes):
"""Makes a fault-and-striae plot (a.k.a. "Ball of String") for normal faults
with the given strikes, dips, and rakes."""
# Plot the planes
lines = ax.plane(strikes, dips, 'k-', lw=0.5)
# Calculate the position of the rake of the lineations, but don't plot yet
x, y = mplstereonet.rake(strikes, dips, rakes)
# Calculate the direction the arrows should point
# These are all normal faults, so the arrows point away from the center
# For thrusts, it would just be u, v = -x/mag, -y/mag
mag = np.hypot(x, y)
u, v = x / mag, y / mag
# Plot the arrows at the rake locations...
arrows = ax.quiver(x, y, u, v, width=1, headwidth=4, units='dots')
return lines, arrows
def tangent_lineation_plot(ax, strikes, dips, rakes):
"""Makes a tangent lineation plot for normal faults with the given strikes,
dips, and rakes."""
# Calculate the position of the rake of the lineations, but don't plot yet
rake_x, rake_y = mplstereonet.rake(strikes, dips, rakes)
# Calculate the direction the arrows should point
# These are all normal faults, so the arrows point away from the center
# Because we're plotting at the pole location, however, we need to flip this
# from what we plotted with the "ball of string" plot.
mag = np.hypot(rake_x, rake_y)
u, v = -rake_x / mag, -rake_y / mag
# Calculate the position of the poles
pole_x, pole_y = mplstereonet.pole(strikes, dips)
# Plot the arrows centered on the pole locations...
arrows = ax.quiver(pole_x, pole_y, u, v, width=1, headwidth=4, units='dots',
pivot='middle')
return arrows
