## 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. |