Package pygeodesy :: Module ellipsoids
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Module ellipsoids

Classes a_f2Tuple, Ellipsoid, Ellipsoid2, an Ellipsoids registry and a dozen functions to convert equatorial radius, polar radius, eccentricities, flattenings and inverse flattening.

See module datums for more information and other details.


Version: 20.10.05

Classes
  a_f2Tuple
2-Tuple (a, f) specifying an ellipsoid by equatorial radius a (meter) and scalar flattening f.
  Curvature2Tuple
2-Tuple (meridional, prime_vertical) of radii of curvature, both in meter, conventionally.
  Ellipsoid
Ellipsoid with equatorial and polar radius, flattening, inverse flattening and other, often used, cached attributes, supporting spherical and oblate and prolate ellipsoidal models.
  Ellipsoid2
Like Ellipsoid, but specified by equatorial radius and flattening.
Functions
 
a_b2e(a, b)
Return e, the eccentricity for a given equatorial and polar radius.
 
a_b2e2(a, b)
Return e2, the eccentricity squared for a given equatorial and polar radius.
 
a_b2e22(a, b)
Return e22, the 2nd eccentricity squared for a given equatorial and polar radius.
 
a_b2e32(a, b)
Return e32, the 3rd eccentricity squared for a given equatorial and polar radius.
 
a_b2f(a, b)
Return f, the flattening for a given equatorial and polar radius.
 
a_b2f_(a, b)
Return f_, the inverse flattening for a given equatorial and polar radius.
 
a_b2f2(a, b)
Return f2, the 2nd flattening for a given equatorial and polar radius.
 
a_b2n(a, b)
Return n, the 3rd flattening for a given equatorial and polar radius.
 
a_f2b(a, f)
Return b, the polar radius for a given equatorial radius and flattening.
 
a_f_2b(a, f_)
Return b, the polar radius for a given equatorial radius and inverse flattening.
 
b_f2a(b, f)
Return a, the equatorial radius for a given polar radius and flattening.
 
b_f_2a(b, f_)
Return a, the equatorial radius for a given polar radius and inverse flattening.
 
f2e2(f)
Return e2, the eccentricity squared for a given flattening.
 
f2e22(f)
Return e22, the 2nd eccentricity squared for a given flattening.
 
f2e32(f)
Return e32, the 3rd eccentricity squared for a given flattening.
 
f_2f(f_)
Return f, the flattening for a given inverse flattening.
 
f2f_(f)
Return f_, the inverse flattening for a given flattening.
 
f2f2(f)
Return f2, the 2nd flattening for a given flattening.
 
f2n(f)
Return n, the 3rd flattening for a given flattening.
 
n2e2(n)
Return e2, the eccentricity squared for a given 3rd flattening.
 
n2f(n)
Return f, the flattening for a given 3rd flattening.
Variables
  R_MA = 6378137.0
  R_MB = 6356752.0
  R_KM = 6371.008771415
  R_NM = 3440.06953446921
  R_SM = 3958.753395372691
  R_FM = 6371000.0
  R_VM = 6366707.0194937
  __all__ = _ALL_LAZY.ellipsoids
  Ellipsoids = Ellipsoids.Airy1830: Ellipsoid(name='Airy1830', a...
  Ellipsoids.Airy1830
Ellipsoid(name='Airy1830', a=6377563.396, b=6356256.90923729, f_=299.3249646, f=0.00334085, f2=0.00335205, n=0.00167322, e=0.08167337, e2=0.00667054, e22=0.00671533, e32=0.00334643, L=10001126.0807165, R1=6370461.23374576, R2=6370459.65470808, R3=6370453.30994572)
  Ellipsoids.AiryModified
Ellipsoid(name='AiryModified', a=6377340.189, b=6356034.44793853, f_=299.3249646, f=0.00334085, f2=0.00335205, n=0.00167322, e=0.08167337, e2=0.00667054, e22=0.00671533, e32=0.00334643, L=10000776.05340819, R1=6370238.27531284, R2=6370236.69633043, R3=6370230.35179012)
  Ellipsoids.Australia1966
Ellipsoid(name='Australia1966', a=6378160, b=6356774.71919531, f_=298.25, f=0.00335289, f2=0.00336417, n=0.00167926, e=0.08182018, e2=0.00669454, e22=0.00673966, e32=0.00335851, L=10002001.39064442, R1=6371031.5730651, R2=6371029.9824858, R3=6371023.59124343)
  Ellipsoids.Bessel1841
Ellipsoid(name='Bessel1841', a=6377397.155, b=6356078.962818, f_=299.1528128, f=0.00334277, f2=0.00335398, n=0.00167418, e=0.08169683, e2=0.00667437, e22=0.00671922, e32=0.00334836, L=10000855.76443237, R1=6370291.09093933, R2=6370289.51012659, R3=6370283.15821522)
  Ellipsoids.CPM1799
Ellipsoid(name='CPM1799', a=6375738.7, b=6356671.92557493, f_=334.39, f=0.00299052, f2=0.00299949, n=0.0014975, e=0.07727934, e2=0.0059721, e22=0.00600798, e32=0.00299499, L=10000017.52721564, R1=6369383.10852498, R2=6369381.8434158, R3=6369376.76247021)
  Ellipsoids.Clarke1866
Ellipsoid(name='Clarke1866', a=6378206.4, b=6356583.8, f_=294.97869821, f=0.00339008, f2=0.00340161, n=0.00169792, e=0.08227185, e2=0.00676866, e22=0.00681478, e32=0.00339582, L=10001888.04298286, R1=6370998.86666667, R2=6370997.240633, R3=6370990.70659881)
  Ellipsoids.Clarke1880
Ellipsoid(name='Clarke1880', a=6378249.145, b=6356514.86954978, f_=293.465, f=0.00340756, f2=0.00341921, n=0.00170669, e=0.0824834, e2=0.00680351, e22=0.00685012, e32=0.00341337, L=10001867.55164747, R1=6371004.38651659, R2=6371002.74366963, R3=6370996.1419165)
  Ellipsoids.Clarke1880IGN
Ellipsoid(name='Clarke1880IGN', a=6378249.2, b=6356515, f_=293.46602129, f=0.00340755, f2=0.0034192, n=0.00170668, e=0.08248326, e2=0.00680349, e22=0.00685009, e32=0.00341336, L=10001867.69724906, R1=6371004.46666667, R2=6371002.82383112, R3=6370996.22212394)
  Ellipsoids.Clarke1880Mod
Ellipsoid(name='Clarke1880Mod', a=6378249.145, b=6356514.96582849, f_=293.4663, f=0.00340755, f2=0.0034192, n=0.00170668, e=0.08248322, e2=0.00680348, e22=0.00685009, e32=0.00341335, L=10001867.62720001, R1=6371004.4186095, R2=6371002.77577708, R3=6370996.17408252)
  Ellipsoids.Delambre1810
Ellipsoid(name='Delambre1810', a=6376428, b=6355957.92616372, f_=311.5, f=0.00321027, f2=0.00322061, n=0.00160772, e=0.08006397, e2=0.00641024, e22=0.0064516, e32=0.00321543, L=9999998.98395793, R1=6369604.64205457, R2=6369603.18419749, R3=6369597.32739068)
  Ellipsoids.Engelis1985
Ellipsoid(name='Engelis1985', a=6378136.05, b=6356751.32272154, f_=298.2566, f=0.00335282, f2=0.0033641, n=0.00167922, e=0.08181928, e2=0.00669439, e22=0.00673951, e32=0.00335844, L=10001964.20447208, R1=6371007.80757385, R2=6371006.21707085, R3=6370999.82613572)
  Ellipsoids.Everest1969
Ellipsoid(name='Everest1969', a=6377295.664, b=6356094.667915, f_=300.8017, f=0.00332445, f2=0.00333554, n=0.00166499, e=0.08147298, e2=0.00663785, e22=0.0066822, e32=0.00332998, L=10000788.3115495, R1=6370228.665305, R2=6370227.10178537, R3=6370220.81951617)
  Ellipsoids.Fisher1968
Ellipsoid(name='Fisher1968', a=6378150, b=6356768.33724438, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10001988.52191361, R1=6371022.77908146, R2=6371021.18903735, R3=6371014.79995034)
  Ellipsoids.GEM10C
Ellipsoid(name='GEM10C', a=6378137, b=6356752.31424783, f_=298.2572236, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001965.7293148, R1=6371008.77141594, R2=6371007.18091936, R3=6371000.79001004)
  Ellipsoids.GRS67
Ellipsoid(name='GRS67', a=6378160, b=6356774.51609071, f_=298.24716743, f=0.00335292, f2=0.0033642, n=0.00167928, e=0.08182057, e2=0.00669461, e22=0.00673973, e32=0.00335854, L=10002001.2312605, R1=6371031.50536357, R2=6371029.91475409, R3=6371023.52339014)
  Ellipsoids.GRS80
Ellipsoid(name='GRS80', a=6378137, b=6356752.31414035, f_=298.2572221, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001965.72923046, R1=6371008.77138012, R2=6371007.18088351, R3=6371000.78997413)
  Ellipsoids.Helmert1906
Ellipsoid(name='Helmert1906', a=6378200, b=6356818.16962789, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10002066.93013953, R1=6371072.7232093, R2=6371071.13315272, R3=6371064.74401563)
  Ellipsoids.IERS1989
Ellipsoid(name='IERS1989', a=6378136, b=6356751.30156878, f_=298.257, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181922, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001964.14856985, R1=6371007.76718959, R2=6371006.17669088, R3=6370999.78577296)
  Ellipsoids.IERS1992TOPEX
Ellipsoid(name='IERS1992TOPEX', a=6378136.3, b=6356751.61659215, f_=298.25722356, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001964.63159783, R1=6371008.07219738, R2=6371006.48170097, R3=6371000.09079235)
  Ellipsoids.IERS2003
Ellipsoid(name='IERS2003', a=6378136.6, b=6356751.85797165, f_=298.25642, f=0.00335282, f2=0.0033641, n=0.00167922, e=0.0818193, e2=0.0066944, e22=0.00673951, e32=0.00335844, L=10001965.05683465, R1=6371008.35265722, R2=6371006.76215217, R3=6371000.37120876)
  Ellipsoids.Intl1924
Ellipsoid(name='Intl1924', a=6378388, b=6356911.94612795, f_=297, f=0.003367, f2=0.00337838, n=0.00168634, e=0.08199189, e2=0.00672267, e22=0.00676817, e32=0.00337267, L=10002288.29898944, R1=6371229.31537598, R2=6371227.71133444, R3=6371221.26587487)
  Ellipsoids.Intl1967
Ellipsoid(name='Intl1967', a=6378157.5, b=6356772.2, f_=298.24961539, f=0.0033529, f2=0.00336418, n=0.00167926, e=0.08182023, e2=0.00669455, e22=0.00673967, e32=0.00335852, L=10001997.44859308, R1=6371029.06666667, R2=6371027.47608389, R3=6371021.08482752)
  Ellipsoids.Krassovski1940
Ellipsoid(name='Krassovski1940', a=6378245, b=6356863.01877305, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10002137.49754285, R1=6371117.67292435, R2=6371116.08285656, R3=6371109.69367439)
  Ellipsoids.Krassowsky1940
Ellipsoid(name='Krassowsky1940', a=6378245, b=6356863.01877305, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10002137.49754285, R1=6371117.67292435, R2=6371116.08285656, R3=6371109.69367439)
  Ellipsoids.Maupertuis1738
Ellipsoid(name='Maupertuis1738', a=6397300, b=6363806.28272251, f_=191, f=0.0052356, f2=0.00526316, n=0.00262467, e=0.10219488, e2=0.01044379, e22=0.01055402, e32=0.00524931, L=10022566.69846922, R1=6386135.42757417, R2=6386131.54144847, R3=6386115.88628229)
  Ellipsoids.Mercury1960
Ellipsoid(name='Mercury1960', a=6378166, b=6356784.28360711, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10002013.61254591, R1=6371038.76120237, R2=6371037.17115427, R3=6371030.78205124)
  Ellipsoids.Mercury1968Mod
Ellipsoid(name='Mercury1968Mod', a=6378150, b=6356768.33724438, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10001988.52191361, R1=6371022.77908146, R2=6371021.18903735, R3=6371014.79995034)
  Ellipsoids.NWL1965
Ellipsoid(name='NWL1965', a=6378145, b=6356759.76948868, f_=298.25, f=0.00335289, f2=0.00336417, n=0.00167926, e=0.08182018, e2=0.00669454, e22=0.00673966, e32=0.00335851, L=10001977.86818326, R1=6371016.58982956, R2=6371014.999254, R3=6371008.60802666)
  Ellipsoids.OSU86F
Ellipsoid(name='OSU86F', a=6378136.2, b=6356751.51693008, f_=298.2572236, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001964.47478349, R1=6371007.97231003, R2=6371006.38181364, R3=6370999.99090512)
  Ellipsoids.OSU91A
Ellipsoid(name='OSU91A', a=6378136.3, b=6356751.6165948, f_=298.2572236, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001964.63159991, R1=6371008.07219827, R2=6371006.48170186, R3=6371000.09079324)
  Ellipsoids.Plessis1817
Ellipsoid(name='Plessis1817', a=6376523, b=6355862.93325557, f_=308.64, f=0.00324002, f2=0.00325055, n=0.00162264, e=0.08043347, e2=0.00646954, e22=0.00651167, e32=0.00324527, L=9999999.1100364, R1=6369636.31108519, R2=6369634.82608583, R3=6369628.85999667)
  Ellipsoids.SGS85
Ellipsoid(name='SGS85', a=6378136, b=6356751.30156878, f_=298.257, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181922, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001964.14856985, R1=6371007.76718959, R2=6371006.17669087, R3=6370999.78577296)
  Ellipsoids.SoAmerican1969
Ellipsoid(name='SoAmerican1969', a=6378160, b=6356774.71919531, f_=298.25, f=0.00335289, f2=0.00336417, n=0.00167926, e=0.08182018, e2=0.00669454, e22=0.00673966, e32=0.00335851, L=10002001.39064442, R1=6371031.5730651, R2=6371029.98248581, R3=6371023.59124343)
  Ellipsoids.Sphere
Ellipsoid(name='Sphere', a=6371008.771415, b=6371008.771415, f_=0, f=0, f2=0, n=0, e=0, e2=0, e22=0, e32=0, L=10007557.17611675, R1=6371008.771415, R2=6371008.771415, R3=6371008.771415)
  Ellipsoids.SphereAuthalic
Ellipsoid(name='SphereAuthalic', a=6371000, b=6371000, f_=0, f=0, f2=0, n=0, e=0, e2=0, e22=0, e32=0, L=10007543.39801029, R1=6371000, R2=6371000, R3=6371000)
  Ellipsoids.SpherePopular
Ellipsoid(name='SpherePopular', a=6378137, b=6378137, f_=0, f=0, f2=0, n=0, e=0, e2=0, e22=0, e32=0, L=10018754.17139462, R1=6378137, R2=6378137, R3=6378137)
  Ellipsoids.Struve1860
Ellipsoid(name='Struve1860', a=6378298.3, b=6356657.14266956, f_=294.73, f=0.00339294, f2=0.00340449, n=0.00169935, e=0.0823065, e2=0.00677436, e22=0.00682056, e32=0.00339869, L=10002017.83655713, R1=6371084.58088985, R2=6371082.95208988, R3=6371076.40691418)
  Ellipsoids.WGS60
Ellipsoid(name='WGS60', a=6378165, b=6356783.28695944, f_=298.3, f=0.00335233, f2=0.00336361, n=0.00167898, e=0.08181333, e2=0.00669342, e22=0.00673853, e32=0.00335795, L=10002012.04438139, R1=6371037.76231981, R2=6371036.17227197, R3=6371029.78316993)
  Ellipsoids.WGS66
Ellipsoid(name='WGS66', a=6378145, b=6356759.76948868, f_=298.25, f=0.00335289, f2=0.00336417, n=0.00167926, e=0.08182018, e2=0.00669454, e22=0.00673966, e32=0.00335851, L=10001977.86818326, R1=6371016.58982956, R2=6371014.999254, R3=6371008.60802666)
  Ellipsoids.WGS72
Ellipsoid(name='WGS72', a=6378135, b=6356750.52001609, f_=298.26, f=0.00335278, f2=0.00336406, n=0.0016792, e=0.08181881, e2=0.00669432, e22=0.00673943, e32=0.0033584, L=10001962.74919858, R1=6371006.84000536, R2=6371005.24953886, R3=6370998.85875069)
  Ellipsoids.WGS84
Ellipsoid(name='WGS84', a=6378137, b=6356752.31424518, f_=298.25722356, f=0.00335281, f2=0.00336409, n=0.00167922, e=0.08181919, e2=0.00669438, e22=0.0067395, e32=0.00335843, L=10001965.72931272, R1=6371008.77141506, R2=6371007.18091847, R3=6371000.79000915)
Function Details

a_b2e (a, b)

 

Return e, the eccentricity for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The eccentricity (float or 0), sqrt(1 - (b / a)**2).

Note: The result is 0 for prolate and near-spherical ellipsoids.

a_b2e2 (a, b)

 

Return e2, the eccentricity squared for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The eccentricity squared (float or 0), 1 - (b / a)**2.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2e22 (a, b)

 

Return e22, the 2nd eccentricity squared for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The 2nd eccentricity squared (float or 0), (a / b)**2 - 1.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2e32 (a, b)

 

Return e32, the 3rd eccentricity squared for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The 3rd eccentricity squared (float or 0), (a**2 - b**2) / (a**2 + b**2).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2f (a, b)

 

Return f, the flattening for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The flattening (float or 0), (a - b) / a.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2f_ (a, b)

 

Return f_, the inverse flattening for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The inverse flattening (float or 0), a / (a - b).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2f2 (a, b)

 

Return f2, the 2nd flattening for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The 2nd flattening (float or 0), (a - b) / b.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_b2n (a, b)

 

Return n, the 3rd flattening for a given equatorial and polar radius.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • b - Polar (minor) radius (scalar > 0).
Returns:
The 3rd flattening (float or 0), (a - b) / (a + b).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

a_f2b (a, f)

 

Return b, the polar radius for a given equatorial radius and flattening.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • f - Flattening (scalar < 1).
Returns:
The polar (minor) radius (float), a * (1 - f).

a_f_2b (a, f_)

 

Return b, the polar radius for a given equatorial radius and inverse flattening.

Arguments:
  • a - Equatorial (major) radius (scalar > 0).
  • f_ - Inverse flattening (scalar >>> 1).
Returns:
The polar (minor) radius (float), a * (f_ - 1) / f_.

b_f2a (b, f)

 

Return a, the equatorial radius for a given polar radius and flattening.

Arguments:
  • b - Polar (minor) radius (scalar > 0).
  • f - Flattening (scalar < 1).
Returns:
The equatorial (major) radius (float), b / (1 - f).

b_f_2a (b, f_)

 

Return a, the equatorial radius for a given polar radius and inverse flattening.

Arguments:
  • b - Polar (minor) radius (scalar > 0).
  • f_ - Inverse flattening (scalar >>> 1).
Returns:
The equatorial (major) radius (float), b * f_ / (f_ - 1).

f2e2 (f)

 

Return e2, the eccentricity squared for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The (1st) eccentricity squared (float < 1), f * (2 - f).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Eccentricity conversions and Flattening.

f2e22 (f)

 

Return e22, the 2nd eccentricity squared for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The 2nd eccentricity squared (float > -1 or INF), f * (2 - f) / (1 - f)**2.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Eccentricity conversions.

f2e32 (f)

 

Return e32, the 3rd eccentricity squared for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The 3rd eccentricity squared (float), f * (2 - f) / (1 + (1 - f)**2).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Eccentricity conversions.

f_2f (f_)

 

Return f, the flattening for a given inverse flattening.

Arguments:
  • f_ - Inverse flattening (scalar >>> 1).
Returns:
The flattening (float or 0), 1 / f_.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

f2f_ (f)

 

Return f_, the inverse flattening for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The inverse flattening (float or 0), 1 / f.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

f2f2 (f)

 

Return f2, the 2nd flattening for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The 2nd flattening (float or INF), f / (1 - f).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Eccentricity conversions and Flattening.

f2n (f)

 

Return n, the 3rd flattening for a given flattening.

Arguments:
  • f - Flattening (scalar < 1).
Returns:
The 3rd flattening (-1 < float < 1), f / (2 - f).

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Eccentricity conversions and Flattening.

n2e2 (n)

 

Return e2, the eccentricity squared for a given 3rd flattening.

Arguments:
  • n - The 3rd flattening (-1 < scalar < 1).
Returns:
The (1st) eccentricity squared (float or -INF), 4 * n / (1 + n)**2.

Note: The result is negative for prolate or 0 for near-spherical ellipsoids.

See Also: Flattening.

n2f (n)

 

Return f, the flattening for a given 3rd flattening.

Arguments:
  • n - The 3rd flattening (-1 <= scalar <= 1).
Returns:
The flattening (float or -INF), 2 * n / (1 + n).

Variables Details

Ellipsoids

Value:
Ellipsoids.Airy1830: Ellipsoid(name='Airy1830', a=6377563.396, b=63562\
56.90923729, f_=299.3249646, f=0.00334085, f2=0.00335205, n=0.00167322\
, e=0.08167337, e2=0.00667054, e22=0.00671533, e32=0.00334643, L=10001\
126.0807165, R1=6370461.23374576, R2=6370459.65470808, R3=6370453.3099\
4572),
Ellipsoids.AiryModified: Ellipsoid(name='AiryModified', a=6377340.189,\
 b=6356034.44793853, f_=299.3249646, f=0.00334085, f2=0.00335205, n=0.\
00167322, e=0.08167337, e2=0.00667054, e22=0.00671533, e32=0.00334643,\
...