norm_potential

  • Calculates the normal potential at a given latitude and height

Calling Sequence

from geoid_toolkit.norm_potential import norm_potential
U, dU_dr, dU_dtheta = norm_potential(lat, lon, h, 'WGS84', lmax)

Source code

geoid_toolkit.norm_potential(lat, lon, h, refell, lmax)[source]

Calculates the normal potential following Barthelmes [1], Hofmann-Wellenhof and Moritz [4], Moazezi and Zomorrodian [8], Molodensky [9]

Parameters:
lat: float

latitude in degrees

lon: float

longitude in degrees

h: float

ellipsoidal height in meters

refell: 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

lmax: int

maximum spherical harmonic degree

Returns:
U: float

normal potential at height

dU_dr: float

derivative of normal potential with respect to radius

dU_dtheta: float

derivative of normal potential with respect to theta

geoid_toolkit.norm_potential.cosine_even_zonals(J2, e, n)[source]

Calculate even zonal harmonics using J2 and first eccentricity

Parameters:
J2: float

Oblateness

e: float

First eccentricity

n: int

spherical harmonic degree

Returns:
J2n: float

Even zonal harmonics