deltametrics.section.CircularSection

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

(png, hires.png)

Warning

This section will not work for unequal dim1 and dim2 coordinate spacing.

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, optional) – The radius of the section in dimensional coordinates. 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.

• origin (tuple of float, optional) – The origin of the circular section in dimensional coordinates, specified as a two-element tuple (dim1, dim2). 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 this values can be determined. I.e., the origin defaults to be centered over the channel inlet.

• radius_idx (float, int, optional) – The radius of the section in cell indices. This is the distance to locate the section from the origin. Mutually exclusive with radius.

• origin_idx (tuple of int, optional) – The origin of the circular section in dimensional coordinates, specified as a two-element tuple (dim1, dim2). This is the center of the circle. Mutually exclusive with origin.

• **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

Create a CircularSection that is registered to a DataCube with radius =1200, and using the default origin options:

>>> golfcube = dm.sample_data.golf()
>>> golfcube.register_section(
...     'circular', dm.section.CircularSection(radius=1200))

>>> # 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['circular'].show_trace('r--', ax=ax[0])
>>> golfcube.sections['circular'].show('velocity', ax=ax[1])
>>> plt.show()

(png, hires.png)

Create a CircularSection that is registered to a StratigraphyCube with radius index =50, and the origin against the domain edge (using the origin_idx option):

>>> golfcube = dm.sample_data.golf()
>>> golfstrat = dm.cube.StratigraphyCube.from_DataCube(golfcube, dz=0.1)
>>> golfstrat.register_section(
...     'circular', dm.section.CircularSection(radius_idx=50,
...                                            origin_idx=(0, 100)))

>>> # 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)
>>> golfstrat.sections['circular'].show_trace('r--', ax=ax[0])
>>> golfstrat.sections['circular'].show('velocity', ax=ax[1])
>>> plt.show()

(png, hires.png)

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

Identify coordinates defining the section.

Parameters:

• section_type (str) – String identifying the type of Section being instantiated.

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

• name (str, optional) – An optional name for the Section object, helpful for maintaining and keeping track of multiple Section objects of the same type. This is disctinct from the section_type. The name is used internally if you use the register_section method of a Cube. Notes

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, radius_idx, ...])	Identify coordinates defining the section.
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

idx_trace	Alias for self.trace_idx.
length	Length of section in dimensional coordinates.
name	Section name.
origin	Origin of the section in dimensional coordinates.
radius	Radius of the section in dimensional coordinates.
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.
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 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 origin

Origin of the section in dimensional coordinates.

Hint

Returned as a point (dim1, dim2), so will need to be reversed for plotting in Cartesian coordinates.

property radius

Radius of the section in dimensional coordinates.

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 z

Up-section (vertical) coordinate.