deltametrics.section.StrikeSection

class deltametrics.section.StrikeSection(*args, distance=None, distance_idx=None, length=None, y=None, x=None, **kwargs)

Strike section object.

Section oriented parallel to the dim2 axis. Specify the location of the strike section with distance and length or distance_idx and length keyword parameters.

(png, hires.png)

Hint

Either distance or distance_idx must be specified.

Parameters:

• *args (DataCube or StratigraphyCube) – The Cube object to link for underlying data. This option should be ommitted if using the register_section method of a Cube.

• distance (float, optional) – Distance in `dim1` coordinates from the dim1 lower domain edge to place the section. The section location will be interpolated to the nearest grid cell. Mutually exclusive with distance_idx.

• distance_idx (int, optional) – Distance in cell indices from the dim1 lower domain edge to place the section. Mutually exclusive with distance.

• length (tuple or list of int or float, optional) – A two-element tuple specifying the bounding points of the section in the dim2 axis. Values are treated as cell indices if distance_idx is given and as dim2 coordinates if distance is given. If no value is supplied, the section is drawn across the entire dim2 axis (i.e., across the whole domain).

• y (int, optional, deprecated) – The number of cells in from the dim1 lower domain edge. If used, the value is internally coerced to distance_idx.

• x (int, optional, deprecated) – The limits of the section. Defaults to the full dim2 domain width. Specify as a two-element tuple or list of int, giving the lower and upper bounds of indices to span the section.

• **kwargs – Keyword arguments are passed to BaseSection.__init__(). Supported options are name.

Returns:

section – StrikeSection object with specified parameters. The section is automatically connected to the underlying Cube data source if the register_section method of a Cube is used to set up the section, or the Cube is passed as the first positional argument during instantiation.

Return type:

StrikeSection

Examples

Create a StrikeSection that is registered to a DataCube at specified distance in dim1 coordinates, and spans the entire model domain:

>>> golfcube = dm.sample_data.golf()
>>> golfcube.register_section('strike', dm.section.StrikeSection(distance=3500))

>>> # show the location and the "velocity" variable
>>> fig, ax = plt.subplots(2, 1, figsize=(8, 4))
>>> golfcube.quick_show('eta', idx=-1, ax=ax[0], ticks=True)
>>> golfcube.sections['strike'].show_trace('r--', ax=ax[0])
>>> golfcube.sections['strike'].show('velocity', ax=ax[1])
>>> plt.show()

(png, hires.png)

Create a StrikeSection that is registered to a DataCube at specified distance_idx index =10, and spans the entire model domain:

>>> golfcube = dm.sample_data.golf()
>>> golfcube.register_section('strike', dm.section.StrikeSection(distance_idx=10))

>>> # show the location and the "velocity" variable
>>> fig, ax = plt.subplots(2, 1, figsize=(8, 4))
>>> golfcube.quick_show('eta', idx=-1, ax=ax[0], ticks=True)
>>> golfcube.sections['strike'].show_trace('r--', ax=ax[0])
>>> golfcube.sections['strike'].show('velocity', ax=ax[1])
>>> plt.show()

(png, hires.png)

Create a StrikeSection that is registered to a StratigraphyCube at specified distance in dim1 coordinates, and spans only a range in the middle of the domain:

>>> golfcube = dm.sample_data.golf()
>>> golfstrat = dm.cube.StratigraphyCube.from_DataCube(golfcube, dz=0.1)
>>> golfstrat.register_section(
...     'strike_part', dm.section.StrikeSection(distance=1500, length=(2000, 5000)))

>>> # show the location and the "time" variable
>>> fig, ax = plt.subplots(2, 1, figsize=(8, 4))
>>> golfcube.quick_show('eta', idx=-1, ax=ax[0], ticks=True)
>>> golfstrat.sections['strike_part'].show_trace('r--', ax=ax[0])
>>> golfstrat.sections['strike_part'].show('time', ax=ax[1])
>>> plt.show()

(png, hires.png)

__init__(*args, distance=None, distance_idx=None, length=None, y=None, x=None, **kwargs)

Initialization for the LineSection.

The LineSection is the base class for Strike and Dip sections, as these share identical input arguments, and processing steps, but differ in which direction the line is drawn.

Note

the RadialSection does not subclass LineSection.

Methods

__init__(*args[, distance, distance_idx, ...])	Initialization for the LineSection.
connect(InputInstance[, name])	Connect this Section instance to a Cube instance.
show(*args[, style, data, label, colorbar, ...])	Show the section.
show_trace(*args[, ax, autoscale])	Plot section trace (x-y plane path).

Attributes

distance	Distance of section from reference edge, in perpendicular-reference coordinates.
distance_idx	Distance of section from from reference edge, in perpendicular-reference indices.
idx_trace	Alias for self.trace_idx.
length	Length of section in dimensional coordinates.
name	Section name.
s	Along-section coordinate.
shape	Section shape.
strat_attr	Stratigraphic attributes data object.
trace	Coordinates of the section in the dim1-dim2 plane.
trace_idx	Indices of section points in the dim1-dim2 plane.
variables	List of variables.
x	Deprecated.
y	Deprecated.
z	Up-section (vertical) coordinate.

__getitem__(var)

Get a slice of the section.

Slicing the section instance creates an xarray DataArray instance from data, for variable var and maintaining the data coordinates.

Note

We only support slicing by string.

Parameters:

var (str) – Which variable to slice.

Returns:

data – The underlying data returned as an xarray DataArray, maintaining coordinates.

Return type:

DataArray

connect(InputInstance, name=None)

Connect this Section instance to a Cube instance.

property distance

Distance of section from reference edge, in perpendicular-reference coordinates.

property distance_idx

Distance of section from from reference edge, in perpendicular-reference indices.

property idx_trace

Alias for self.trace_idx.

property length

Length of section in dimensional coordinates.

property name

Section name.

Helpful to differentiate multiple Section objects.

property s

Along-section coordinate.

property shape

Section shape.

Simply a tuple equivalent to (len(z), len(s))

show(*args, style='shaded', data=None, label=False, colorbar=True, colorbar_label=False, ax=None)

Show the section.

Method enumerates convenient routines for visualizing sections of data and stratigraphy. Includes support for multiple data style and multiple data choices as well.

Note

The colors for style=’lines’ are determined from the left-end edge node, and colors for the style=’shaded’ mesh are determined from the lower-left-end edge node of the quad.

Parameters:

• SectionAttribute (str, SectionVariableInstance) – Which attribute to show. Can be a string for a named Cube attribute, or any arbitrary data. Additionally, pass no arguments and the first variable in the underlying data source list will be used.

• style (str, optional) – What style to display the section with. Choices are ‘mesh’ or ‘line’.

• data (str, optional) – Argument passed to get_display_arrays or get_display_lines. Supported options are ‘spacetime’, ‘preserved’, and ‘stratigraphy’. Default is to display full spacetime plot for section generated from a DataCube, and stratigraphy for a StratigraphyCube section.

• label (bool, str, optional) – Display a label of the variable name on the plot. Default is False, display nothing. If label=True, the label name from the VariableSet is used. Other arguments are attempted to coerce to str, and the literal is diplayed.

• colorbar (bool, optional) – Whether a colorbar is appended to the axis.

• colorbar_label (bool, str, optional) – Display a label of the variable name along the colorbar. Default is False, display nothing. If label=True, the label name from the VariableSet is used. Other arguments are attempted to coerce to str, and the literal is diplayed.

• ax (Axes object, optional) – A matplotlib Axes object to plot the section. Optional; if not provided, a call is made to plt.gca() to get the current (or create a new) Axes object.

Examples

Example 1: Display the velocity spacetime section of a DataCube.

>>> golfcube = dm.sample_data.golf()
>>> golfcube.register_section(
...     'demo', dm.section.StrikeSection(distance_idx=5))
>>> golfcube.sections['demo'].show('velocity')

(png, hires.png)

Note that the last line above is functionally equivalent to golfcube.show_section('demo', 'velocity').

Example 2: Display a section, with “quick” stratigraphy, as the depth attribute, displaying several different section styles.

>>> golfcube = dm.sample_data.golf()
>>> golfcube.stratigraphy_from('eta')
>>> golfcube.register_section(
...     'demo', dm.section.StrikeSection(distance=250))

>>> fig, ax = plt.subplots(4, 1, sharex=True, figsize=(6, 9))
>>> golfcube.sections['demo'].show('depth', data='spacetime',
...                                 ax=ax[0], label='spacetime')
>>> golfcube.sections['demo'].show('depth', data='preserved',
...                                ax=ax[1], label='preserved')
>>> golfcube.sections['demo'].show('depth', data='stratigraphy',
...                                ax=ax[2], label='quick stratigraphy')
>>> golfcube.sections['demo'].show('depth', style='lines', data='stratigraphy',
...                                ax=ax[3], label='quick stratigraphy')          # noqa: E501

(png, hires.png)

show_trace(*args, ax=None, autoscale=False, **kwargs)

Plot section trace (x-y plane path).

Plot the section trace (trace) onto an x-y planview.

Parameters:

• *args – Passed to matplotlib plot().

• ax (Axes object, optional) – A matplotlib Axes object to plot the trace. Optional; if not provided, a call is made to plt.gca() to get the current (or create a new) Axes object.

• autoscale (bool) – Whether to rescale the axis based on the limits of the section. Manipulates the matplotlib autoscale attribute. Default is False.

• **kwargs – Passed to matplotlib plot().

property strat_attr

Stratigraphic attributes data object.

Raises:

NoStratigraphyError – If no stratigraphy information is found for the section.

property trace

Coordinates of the section in the dim1-dim2 plane.

Note

stack of [dim2, dim1].

property trace_idx

Indices of section points in the dim1-dim2 plane.

property variables

List of variables.

property x

Deprecated. Use length_idx.

Start and end indices of section.

property y

Deprecated. Use distance_idx.

property z

Up-section (vertical) coordinate.