Subclasses

Subclass name Description
SHGravRealCoeffs Real gravitational potential spherical harmonic coefficient class.

Initialization

Initialization method Description
x = SHGravCoeffs.from_array() Initialize using coefficients from an array.
x = SHGravCoeffs.from_random() Initialize using random coefficients with a prescribed power spectrum.
x = SHGravCoeffs.from_zeros() Initialize with coefficients set to zero.
x = SHGravCoeffs.from_file() Initialize using coefficients from a file.
x = SHGravCoeffs.from_shape() Initialize using the gravitational potential predicted from surface relief.

Class attributes

Attribute Description
lmax The maximum spherical harmonic degree of the coefficients.
coeffs The raw coefficients with the specified normalization and phase conventions.
gm The gravitational constant times the mass that is associated with the gravitational potential coefficients.
r0 The reference radius of the gravitational potential coefficients.
omega The angular rotation rate of the body.
normalization The normalization of the coefficients: '4pi', 'ortho', 'schmidt', or 'unnorm'.
csphase Defines whether the Condon-Shortley phase is used (1) or not (-1).
mask A boolean mask that is True for the permissible values of degree l and order m.
kind The coefficient data type (only 'real' is permissible).
header A list of values from the header line of the input file used to initialize the class.

Class methods

Method Description
degrees() Return an array listing the spherical harmonic degrees from 0 to lmax.
spectrum() Return the spectrum of the function.
set_omega() Set the angular rotation rate of the body.
set_coeffs() Set coefficients in-place to specified values.
change_ref() Return a new class instance referenced to a different gm, r0, or omega.
rotate() Rotate the coordinate system used to express the spherical harmonics coefficients and return a new class instance.
convert() Return a new class instance using a different normalization convention.
pad() Return a new class instance that is zero padded or truncated to a different lmax.
expand() Calculate the three vector components of the gravity field, the total field, and the gravitational potential, and return an SHGravGrid class instance.
tensor() Calculate the 9 components of the gravity tensor and return an SHGravTensor class instance.
geoid() Calculate the height of the geoid and return an SHGeoid class instance.
plot_spectrum() Plot the spectrum as a function of spherical harmonic degree.
plot_spectrum2d() Plot the spectrum of all spherical-harmonic coefficients.
to_array() Return an array of spherical harmonics coefficients with a different normalization convention.
to_file() Save raw spherical harmonic coefficients to a text or binary file.
copy() Return a copy of the class instance.
info() Print a summary of the data stored in the SHGravCoeffs instance.
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