verde.datasets.CheckerBoard¶

class verde.datasets.CheckerBoard(amplitude=1000, region=(0, 5000, -5000, 0), w_east=None, w_north=None)[source]¶

Generate synthetic data in a checkerboard pattern.

The mathematical model is:

\[f(e, n) = a \sin\left(\frac{2\pi}{w_e} e\right) \cos\left(\frac{2\pi}{w_n} n\right)\]

in which \(e\) is the easting coordinate, \(n\) is the northing coordinate, \(a\) is the amplitude, and \(w_e\) and \(w_n\) are the wavelengths in the east and north directions, respectively.

Parameters

amplitude (float) – The amplitude of the checkerboard undulations.
region (tuple) – The boundaries ([W, E, S, N]) of the region used to generate the synthetic data.
w_east (float) – The wavelength in the east direction. Defaults to half of the West-East size of the evaluating region.
w_north (float) – The wavelength in the north direction. Defaults to half of the South-North size of the evaluating region.

Examples

>>> synth = CheckerBoard()
>>> # Default values for the wavelengths are selected automatically
>>> print(synth.w_east_, synth.w_north_)
2500.0 2500.0
>>> # CheckerBoard.grid produces an xarray.Dataset with data on a grid
>>> grid = synth.grid(shape=(11, 6))
>>> # scatter and profile generate pandas.DataFrame objects
>>> table = synth.scatter()
>>> print(sorted(table.columns))
['easting', 'northing', 'scalars']
>>> profile = synth.profile(point1=(0, 0), point2=(2500, -2500), size=100)
>>> print(sorted(profile.columns))
['distance', 'easting', 'northing', 'scalars']

Methods Summary

`CheckerBoard.filter`(coordinates, data[, weights])	Filter the data through the gridder and produce residuals.
`CheckerBoard.fit`(coordinates, data[, weights])	Fit the gridder to observed data.
`CheckerBoard.get_params`([deep])	Get parameters for this estimator.
`CheckerBoard.grid`([region, shape, spacing, …])	Interpolate the data onto a regular grid.
`CheckerBoard.predict`(coordinates)	Evaluate the checkerboard function on a given set of points.
`CheckerBoard.profile`(point1, point2, size[, …])	Interpolate data along a profile between two points.
`CheckerBoard.scatter`([region, size, …])	Interpolate values onto a random scatter of points.
`CheckerBoard.score`(coordinates, data[, weights])	Score the gridder predictions against the given data.
`CheckerBoard.set_params`(**params)	Set the parameters of this estimator.

CheckerBoard.filter(coordinates, data, weights=None)¶

Filter the data through the gridder and produce residuals.

Calls fit on the data, evaluates the residuals (data - predicted data), and returns the coordinates, residuals, and weights.

No very useful by itself but this interface makes gridders compatible with other processing operations and is used by verde.Chain to join them together (for example, so you can fit a spline on the residuals of a trend).

Parameters

coordinates (tuple of arrays) – Arrays with the coordinates of each data point. Should be in the following order: (easting, northing, vertical, …).
data (array or tuple of arrays) – The data values of each data point. If the data has more than one component, data must be a tuple of arrays (one for each component).
weights (None or array or tuple of arrays) – If not None, then the weights assigned to each data point. If more than one data component is provided, you must provide a weights array for each data component (if not None).

Returns

coordinates, residuals, weights – The coordinates and weights are same as the input. Residuals are the input data minus the predicted data.

CheckerBoard.fit(coordinates, data, weights=None)¶

Fit the gridder to observed data. NOT IMPLEMENTED.

This is a dummy placeholder for an actual method.

Parameters

coordinates (tuple of arrays) – Arrays with the coordinates of each data point. Should be in the following order: (easting, northing, vertical, …).
data (array or tuple of arrays) – The data values of each data point. If the data has more than one component, data must be a tuple of arrays (one for each component).
weights (None or array or tuple of arrays) – If not None, then the weights assigned to each data point. If more than one data component is provided, you must provide a weights array for each data component (if not None).

Returns

self – This instance of the gridder. Useful to chain operations.

CheckerBoard.get_params(deep=True)¶

Get parameters for this estimator.

Parameters: deep (bool, default=True) – If True, will return the parameters for this estimator and contained subobjects that are estimators.
Returns: params (mapping of string to any) – Parameter names mapped to their values.

CheckerBoard.grid(region=None, shape=None, spacing=None, dims=None, data_names=None, projection=None, **kwargs)¶

Interpolate the data onto a regular grid.

The grid can be specified by either the number of points in each dimension (the shape) or by the grid node spacing. See verde.grid_coordinates for details. Other arguments for verde.grid_coordinates can be passed as extra keyword arguments (kwargs) to this method.

If the interpolator collected the input data region, then it will be used if region=None. Otherwise, you must specify the grid region.

Use the dims and data_names arguments to set custom names for the dimensions and the data field(s) in the output xarray.Dataset. Default names will be provided if none are given.

Parameters

region (list = [W, E, S, N]) – The boundaries of a given region in Cartesian or geographic coordinates.
shape (tuple = (n_north, n_east) or None) – The number of points in the South-North and West-East directions, respectively.
spacing (tuple = (s_north, s_east) or None) – The grid spacing in the South-North and West-East directions, respectively.
dims (list or None) – The names of the northing and easting data dimensions, respectively, in the output grid. Defaults to ['northing', 'easting']. NOTE: This is an exception to the “easting” then “northing” pattern but is required for compatibility with xarray.
data_names (list of None) – The name(s) of the data variables in the output grid. Defaults to ['scalars'] for scalar data, ['east_component', 'north_component'] for 2D vector data, and ['east_component', 'north_component', 'vertical_component'] for 3D vector data.
projection (callable or None) – If not None, then should be a callable object projection(easting, northing) -> (proj_easting, proj_northing) that takes in easting and northing coordinate arrays and returns projected northing and easting coordinate arrays. This function will be used to project the generated grid coordinates before passing them into predict. For example, you can use this to generate a geographic grid from a Cartesian gridder.

Returns

grid (xarray.Dataset) – The interpolated grid. Metadata about the interpolator is written to the attrs attribute.

Examples using `verde.datasets.CheckerBoard`¶

Overview¶

Checkerboard function¶

verde.datasets.CheckerBoard¶

Examples using verde.datasets.CheckerBoard¶

Examples using `verde.datasets.CheckerBoard`¶