sequence.shoreline module#

Find the shoreline of a SequenceModelGrid.

This module contains methods for calculating a grid’s shoreline and shelf edge.

class sequence.shoreline.ShorelineFinder(*args, **kwds)[source]#

Bases: Component

Find a grid’s shoreline.

__init__(grid: SequenceModelGrid, alpha: float = 0.0005)[source]#

Create a shoreline finder.

Parameters:

  • grid (SequenceModelGrid) – A Sequence grid.

  • alpha (float, optional) – Parameter used to find the shoreline when interpolating between nodes.

property alpha: float#

Return the alpha parameter used to calculate the shoreline.

run_one_step(dt: float | None = None) → None[source]#

Update the component on time step.

Parameters:

dt (float, optional) – The time step to update the component by. Since this component is not time-varying, this value is ignored.

update() → None[source]#

Update the component one time step to find the new shoreline.

sequence.shoreline.find_shelf_edge(x: ndarray[Any, dtype[floating]], dz: ndarray[Any, dtype[floating]], x_of_shore: ndarray[Any, dtype[floating]] | float = 0.0, alpha: float = 0.0005) → float[source]#

Find the shelf edge based on deposit thickness.

Parameters:

  • x (ndarray of float) – x-positions of the profile.

  • dz (ndarray of float) – Deposit thickness.

  • x_of_shore (float, optional) – The x-position of the shoreline.

  • alpha (float, optional) – Constant used in interpolating the precise location of the shoreline.

Returns:

The x-coordinate of the shelf edge.

Return type:

float

Raises:

ShelfEdgeError – If the data do not contain the shelf edge.

Examples

>>> import numpy as np
>>> from sequence.shoreline import find_shelf_edge

Create a depositional profile where the maximum deposition is at x=1.0.

>>> x = np.arange(50.) / 5.0
>>> deposit = x * np.exp(-x)
>>> find_shelf_edge(x, deposit, x_of_shore=0.0, alpha=1e3)
1.0
sequence.shoreline.find_shelf_edge_by_curvature(x: ndarray[Any, dtype[floating]], z: ndarray[Any, dtype[floating]], sea_level: float = 0.0) → float[source]#

Find the x-coordinate of the shelf edge.

The shelf edge is the location where the curvature of sea-floor elevations is a minimum.

Parameters:

  • x (ndarray of float) – x-positions of the profile.

  • z (ndarray of float) – Elevations of the profile.

  • sea_level (float, optional) – Elevation of sea level.

Returns:

The x-coordinate of the shelf edge.

Return type:

float

Examples

>>> import numpy as np
>>> from sequence.shoreline import find_shelf_edge_by_curvature

>>> x = np.arange(50.)
>>> z = - np.arctan(x / 5.0 - 5.0)
>>> find_shelf_edge_by_curvature(x, z, sea_level=z.max())
22.0
sequence.shoreline.find_shoreline(x: ndarray[Any, dtype[floating]], z: ndarray[Any, dtype[floating]], sea_level: float = 0.0, kind: str = 'cubic') → ndarray[Any, dtype[floating]] | float[source]#

Find the shoreline of a profile.

Parameters:

  • x (array of float) – X-positions of profile.

  • z (array of float) – Elevations along the profile.

  • sea_level (float, optional) – Elevation of sea level.

  • kind (str, optional) – Interpolation method used to find shoreline. Values are the same as those used for scipy.interpolate.interp1d. Default is ‘cubic’.

Returns:

X-position of the shoreline.

Return type:

float

Examples

>>> from sequence.shoreline import find_shoreline
>>> import numpy as np

Create a linearly-dipping profile.

>>> x = np.arange(10.)
>>> z = - x + 5.
>>> z
array([ 5.,  4.,  3.,  2.,  1.,  0., -1., -2., -3., -4.])

Find the shoreline.

>>> find_shoreline(x, z, kind='linear')
5.0
>>> find_shoreline(x, z, sea_level=.25, kind='linear')
4.75

If sea level is higher/lower than the max/min elevation, return the first/last x value.

>>> find_shoreline(x, z, sea_level=100., kind='linear')
0.0
>>> find_shoreline(x, z, sea_level=-100., kind='linear')
9.0
sequence.shoreline.find_shoreline_index(x: ndarray[Any, dtype[floating]], z: ndarray[Any, dtype[floating]], sea_level: float = 0.0) → ndarray[Any, dtype[integer]] | int[source]#

Find the landward-index of the shoreline.

Parameters:

  • x (array of float) – X-positions of profile.

  • z (array of float) – Elevations along the profile.

  • sea_level (float, optional) – Elevation of sea level.

Returns:

Index into z landward of the shoreline.

Return type:

int

Raises:

ValueError – If the profile does not contain a shoreline.

Examples

>>> from sequence.shoreline import find_shoreline_index
>>> import numpy as np

Create a linearly-dipping profile.

>>> x = np.arange(10.)
>>> z = - x + 5.
>>> z
array([ 5.,  4.,  3.,  2.,  1.,  0., -1., -2., -3., -4.])

Find the shoreline.

>>> find_shoreline_index(x, z)
6
>>> find_shoreline_index(x, z, sea_level=.25)
5

If sea level is higher/lower than the max/min elevation, raise a ShorelineError.

>>> find_shoreline_index(x, z, sea_level=100.)
Traceback (most recent call last):
sequence.errors.ShorelineError: No shoreline found. The profile is all below sea level
>>> find_shoreline_index(x, z, sea_level=-100.)
Traceback (most recent call last):
sequence.errors.ShorelineError: No shoreline found. The profile is all above sea level