deltametrics.section.CircularSection

class deltametrics.section.CircularSection(*args, radius=None, origin=None, **kwargs)

Circular section object.

Section drawn as a circular cut, located a along the arc a specified radius from specified origin. Specify the location of the circular section with :obj`radius` and origin keyword parameter options. The circular section trace is interpolated to the nearest integer model domain cells, following the mid-point circle algorithm (circle_to_cells).

Important

The radius and origin parameters must be specified as cell indices (not actual x and y coordinate values). This is a needed patch.

Important

The origin attempts to detect the land width from bed elevation changes, but should use the value of L0 recorded in the netcdf file, or defined in the cube.

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.

• radius (float, int, optional) – The radius of the section. This is the distance to locate the section from the origin. If no value is given, the radius defaults to half of the minimum model domain edge length if it can be determined, otherwise defaults to 1.

• origin (tuple or list of int, optional) – The origin of the circular section. This is the center of the circle. If no value is given, the origin defaults to the center of the x-direction of the model domain, and offsets into the domain a distance of y == L0, if these values can be determined. I.e., the origin defaults to be centered over the channel inlet. If no value is given, and these values cannot be determined, the origin defaults to (0, 0).

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

Returns

section – CircularSection 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

CircularSection

Examples

To create a CircularSection that is registered to a DataCube with radius =30, and using the default origin options:

>>> rcm8cube = dm.sample_data.rcm8()
>>> rcm8cube.register_section('circular', dm.section.CircularSection(radius=30))
>>>
>>> # show the location and the "velocity" variable
>>> fig, ax = plt.subplots(2, 1, figsize=(8, 4))
>>> rcm8cube.show_plan('eta', t=-1, ax=ax[0], ticks=True)
>>> rcm8cube.sections['circular'].show_trace('r--', ax=ax[0])
>>> rcm8cube.sections['circular'].show('velocity', ax=ax[1])
>>> plt.show()

(png, hires.png)

__init__(*args, radius=None, origin=None, **kwargs)

Identify coordinates defining the section.

Parameters

CubeInstance (Cube subclass instance, optional) – Connect to this cube. No connection is made if cube is not provided.

Notes

If no arguments are passed, an empty section not connected to any cube is returned. This cube will will need to be manually connected to have any functionality (via the connect() method).

Methods

__init__(*args[, radius, origin])	Identify coordinates defining the section.
connect(CubeInstance[, name])	Connect this Section instance to a Cube instance.
show(SectionAttribute[, style, data, label, …])	Show the section.
show_trace(*args[, ax])	Plot section trace (x-y plane path).

Attributes

name
s	Along-section coordinate.
shape	Section shape.
strat_attr	Stratigraphic attributes data object.
trace	Coordinates of the section in the x-y plane.
variables	List of variables.
z	Up-section (vertical) coordinate.

__getitem__(var)

Get a slice of the section.

Slicing the section instance creates a SectionVariable instance from data for variable var.

Note

We only support slicing by string.

Parameters

var (str) – Which variable to slice.

Returns

SectionVariable – SectionVariable instance for variable var.

Return type

SectionVariable instance

_compute_section_attrs()

Compute attrs

Compute the along-section coordinate array from x-y pts pairs definining the section.

_compute_section_coords()

Should calculate x-y coordinates of the section.

Sets the value self._x and self._y according to the algorithm of each section initialization.

Warning

When implementing new section types, be sure that self._x and self._y are one-dimensional arrays, or you will get an improperly shaped Section array in return.

connect(CubeInstance, name=None)

Connect this Section instance to a Cube instance.

s

Along-section coordinate.

shape

Section shape.

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

show(SectionAttribute, 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 mutuple 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) – Which attribute to show.

• 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.

>>> rcm8cube = dm.sample_data.rcm8()
>>> rcm8cube.register_section('demo', dm.section.StrikeSection(y=5))
>>> rcm8cube.sections['demo'].show('velocity')

(png, hires.png)

Note that the last line above is functionally equivalent to rcm8cube.show_section('demo', 'velocity').

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

>>> rcm8cube = dm.sample_data.rcm8()
>>> rcm8cube.stratigraphy_from('eta')
>>> rcm8cube.register_section('demo', dm.section.StrikeSection(y=5))

>>> fig, ax = plt.subplots(4, 1, sharex=True, figsize=(6, 9))
>>> rcm8cube.sections['demo'].show('depth', data='spacetime',
...                                 ax=ax[0], label='spacetime')
>>> rcm8cube.sections['demo'].show('depth', data='preserved',
...                                ax=ax[1], label='preserved')
>>> rcm8cube.sections['demo'].show('depth', data='stratigraphy',
...                                ax=ax[2], label='quick stratigraphy')
>>> rcm8cube.sections['demo'].show('depth', style='lines', data='stratigraphy',
...                                ax=ax[3], label='quick stratigraphy')

(png, hires.png)

show_trace(*args, ax=None, **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.

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

strat_attr

Stratigraphic attributes data object.

Raises

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

trace

Coordinates of the section in the x-y plane.

variables

List of variables.

z

Up-section (vertical) coordinate.