read_ICGEM_harmonics

Reads gravity model files and extracts spherical harmonic data from the GFZ International Centre for Global Earth Models (ICGEM)

Calling Sequence

from geoid_toolkit.read_ICGEM_harmonics import read_ICGEM_harmonics
Ylms = read_ICGEM_harmonics(model_file)

Source code

geoid_toolkit.read_ICGEM_harmonics(model_file, **kwargs)[source]

Extract gravity model spherical harmonics from GFZ ICGEM gfc files

Parameters:

model_file: str

full path to gfc spherical harmonic data file

LMAX: int or NoneType, default None

maximum degree and order of output spherical harmonics

ELLIPSOID: str

Reference ellipsoid name

'CLK66': Clarke 1866

'GRS67': Geodetic Reference System 1967

'GRS80': Geodetic Reference System 1980

'HGH80': Hughes 1980 Ellipsoid

'WGS72': World Geodetic System 1972

'WGS84': World Geodetic System 1984

'ATS77': Quasi-earth centred ellipsoid for ATS77

'NAD27': North American Datum 1927

'NAD83': North American Datum 1983

'INTER': International

'KRASS': Krassovsky (USSR)

'MAIRY': Modified Airy (Ireland 1965/1975)

'TOPEX': TOPEX/POSEIDON ellipsoid

'EGM96': EGM 1996 gravity model

TIDE: str or NoneType, default None

Permanent tide system of output gravity fields

'tide_free': no permanent direct and indirect tidal potentials

'mean_tide': permanent tidal potentials (direct and indirect)

'zero_tide': permanent direct tidal potential removed

FLAG: str, default ‘gfc’

Flag denoting data lines

ZIP: bool, default False

Gravity field file is compressed in an archive file

Returns:

l: int: spherical harmonic degree of model
m: int: spherical harmonic order of model
clm: float: cosine spherical harmonics of input data
slm: float: sine spherical harmonics of input data
eclm: float: cosine spherical harmonic standard deviations of type errors
eslm: float: sine spherical harmonic standard deviations of type errors
modelname: str: Name of the gravity model
earth_gravity_constant: str: GM constant of the Earth for gravity model
radius: str: Semi-major axis of the Earth for gravity model
max_degree: str: Maximum degree and order for gravity model
errors: str: Error type of the gravity model
norm: str: Normalization of the spherical harmonics
tide_system: str: Permanent tide system of gravity model