geolime.geostats.variogram.variogram

Data:

Callable	Callable type; Callable[[int], str] is a function of (int) -> str.
List	The central part of internal API.

Classes:

Enum(value)

Generic enumeration.

Functions:

angle_between_vectors(v1, v2)	Compute the angle between two vectors using the dot product
covariance(values, indices)	Compute the covariance given an array of values for a set of pairs
directional_vector(dimension, …[, deg])	Compute directional vector from angles
generate_lags(lag, plag, nlags)	Generate lags array to be used with variogram
in_angle(vdir, atol)	Return a function that checks for an index vector if it belongs to an angular range.
in_range(target, atol)	Check if target angle lies within a range of angles (defined by an angle tolerance)
in_slice(trend, plunge, vdir[, width, height])	Return a function that check whether a vector (cartesian coordinates) lies within a slice (defined by a width and a height in meters)
norm(x[, ord, axis, keepdims])	Matrix or vector norm.
normalize(a, center)	(Adapted from Apach Commons normalizeAngle, MathUtils sources) Normalize an angle in a 2pi; wide interval around a center value.
pairwise(coords)	Computes pairwise distances
plane_to_dir(azimuth, dip, pitch[, deg])	Convert plane angles to line angles.
rot_z(alpha[, deg, clockwise])	Rotation againt the Z axis
rot_zyx(angles[, deg, clockwise])	Example of a convention (RGeoStats)
select_index_from_slice(idx, f)	Compare vectors from a set of indices
select_indices(coords, pwdist, lag, tol, …)	Check whether a set of points (linked to their distances) match the input restricted boundaries.
select_indices_from_angle(idx, f)	Compare vectors from a set of indices
select_indices_from_lag(pwdist, lag, tol)	Check whether a set of distances lie within a lag-range.
semivariance(values, indices[, weights])	Compute the semivariance given an array of values for a set of pairs
variogram(coords, values, lags, tol, …[, …])	Given boundary input arguments (lag and its associated tolerance, angular reference and its associated tolerance), compute the variogram for a set of points (value associated with cartesian coordinates for a specific point)

geolime.geostats.variogram.variogram.covariance(values: numpy.ndarray, indices: numpy.ndarray)

Compute the covariance given an array of values for a set of pairs

Parameters

• values (np.ndarray) – Array of float values

• indices (np.ndarray) – List of pairs (couple of integers) for a specific lag

Returns

Covariance

Return type

float

geolime.geostats.variogram.variogram.directional_vector(dimension: int, geographic_azimuth: float, dip: float, pitch: float, deg: bool = True)

Compute directional vector from angles

Parameters

• dimension (int) – Angle dimension to be set for rotation convention

• geographic_azimuth (float) – z-axis rotation angle

• dip (float) – y-axis rotation angle

• pitch – x-axis rotation angle

• deg – Indicates if input angles are in degrees or not

Returns

Directional vector, trend and plunge

Return type

np.ndarray, float, float

geolime.geostats.variogram.variogram.generate_lags(lag: float, plag: float, nlags: int)

Generate lags array to be used with variogram

Parameters

• lag (float) – Calculation lag in meters

• plag (float) – Tolerance (percentage of lag)

• nlags (int) – Length of array to be generated

Returns

An array of lags and the tolerance in meters

Return type

np.ndarray, float

geolime.geostats.variogram.variogram.in_angle(vdir: numpy.ndarray, atol: float)

Return a function that checks for an index vector if it belongs to an angular range. Intended to be used for performance vectorization.

Parameters

• vdir (np.ndarray) – Directional vector, computed once during initialization

• atol (float) – Angular tolerance in radians

Returns

A function that returns True if vector is in the angular range, False if the vector is outside

Return type

Callable

geolime.geostats.variogram.variogram.in_range(target: float, atol: float)

Check if target angle lies within a range of angles (defined by an angle tolerance)

Parameters

• target (float) – Angle to be checked (in radians)

• atol (float) – Angular tolerance in radians

Returns

if True: target is in range, if False: target is outside range

Return type

bool

geolime.geostats.variogram.variogram.in_slice(trend: float, plunge: float, vdir: numpy.ndarray, width: float = inf, height: float = inf)

Return a function that check whether a vector (cartesian coordinates) lies within a slice (defined by a width and a height in meters)

Parameters

• trend (float) – Angle for y-axis rotation (in radians)

• plunge (float) – Angle for y-axis rotation (in radians)

• vdir (np.ndarray) – Directional vector array

• plunge –

• width (float) – Slicing width (in meters)

• height (float) – Slicing height (in meters)

Returns

A function that returns True if vector is in the slice, False if the vector is outside slice

Return type

Callable

geolime.geostats.variogram.variogram.select_index_from_slice(idx: pandas.core.frame.DataFrame, f: Callable)

Compare vectors from a set of indices

Parameters

• idx (pd.DataFrame) – Dataframe containing indices to be checked

• f (Callable) – Index selector function

Returns

a selection of indices

Return type

pd.DataFrame

geolime.geostats.variogram.variogram.select_indices(coords: numpy.ndarray, pwdist: numpy.ndarray, lag: float, tol: float, atol: float, f_in_angle: Callable, f_in_slice: Callable)

Check whether a set of points (linked to their distances) match the input restricted boundaries. This function will first check if a set of points lie in a lag range. Then will process the indices for angular range conformity. Lastly, the resulting indices are tested against slicing boundaries (if slicing arguments are provided)

Parameters

• coords (np.ndarray) – Cartesian coordinates in float

• pwdist (np.ndarray) – N * N matrix of pairwise distances (in float)

• lag (float) – Lag in meters

• tol (float) – Lag tolerance in meters

• f_in_angle (Callable) – Index selector function for angle

• f_in_slice (Callable) – Index selector function for slice

• atol (float) – Angular tolerance in degrees

Returns

Array of indices (couple of integers)

Return type

np.ndarray

geolime.geostats.variogram.variogram.select_indices_from_angle(idx: pandas.core.frame.DataFrame, f: Callable)

Compare vectors from a set of indices

Parameters

• idx (pd.DataFrame) – Dataframe containing indices to be checked

• f (Callable) – Index selector function

Returns

a selection of indices

Return type

pd.DataFrame

geolime.geostats.variogram.variogram.select_indices_from_lag(pwdist: numpy.ndarray, lag: float, tol: float)

Check whether a set of distances lie within a lag-range.

From geostatsmodels original comment: grab the coordinates in a given range: lag +/- tolerance and take out the repeated elements, since p is a symmetric distance matrix

Parameters

• pwdist (np.ndarray) – N * N pairwise distances

• lag (float) – lag to be compared to (in meters)

• tol (float) – lag tolerance (in meters)

Returns

dataframe of indices lying in a lag tolerance

Return type

pd.DataFrame

geolime.geostats.variogram.variogram.semivariance(values: numpy.ndarray, indices: numpy.ndarray, weights: numpy.ndarray = None)

Compute the semivariance given an array of values for a set of pairs

Parameters

• values (np.ndarray) – Array of float values

• indices (np.ndarray) – List of pairs (couple of integers) for a specific lag

• weights (np.ndarray) – Optional weights array for semivariance computation

Returns

Semivariance value

Return type

float

geolime.geostats.variogram.variogram.variogram(coords: numpy.ndarray, values: numpy.ndarray, lags: List[float], tol: float, geographic_azimuth: float, dip: float, pitch: float, atol: float, slice_width: float = inf, slice_height: float = inf, method: enum.Enum = 'semivariogram', weights: numpy.ndarray = None)

Given boundary input arguments (lag and its associated tolerance, angular reference and its associated tolerance), compute the variogram for a set of points (value associated with cartesian coordinates for a specific point)

Parameters

• coords (np.ndarray) – Array of cartesian coordinates (in float)

• values (np.ndarray) – Array of values associated with points

• lags (List[float]) – List of lags (in meters)

• tol (float) – Lag tolerance in meters

• geographic_azimuth (float) – z-axis rotation angle in degrees

• dip (float) – y-axis rotation angle in degrees

• pitch (float) – x-axis rotation angle in degrees

• atol (float) – Angular tolerance in degrees

• slice_width (float) – Slicing width (in meters)

• slice_height (float) – Slicing height (in meters)

• method (Enum) – Computation method

• weights (np.ndarray) – Optional weights array for semivariance computation

Returns

A variogram dataframe, Isatis compliant output (rank, number of pairs, input lag, average distance, variogram value and indices)

Return type

pd.DataFrame