Package pygeodesy :: Module datums |
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# Module datums

Datums and transformations thereof.

Classes Datum and Transform and registries Datums and Transforms, respectively.

Pure Python implementation of geodesy tools for ellipsoidal earth models, including datums and ellipsoid parameters for different geographic coordinate systems and methods for converting between them and to cartesian coordinates. Transcoded from JavaScript originals by (C) Chris Veness 2005-2016 and published under the same MIT Licence**, see latlon-ellipsoidal.js.

Historical geodetic datums: a latitude/longitude point defines a geographic location on, above or below the earth’s surface. Latitude is measured in degrees from the equator, lomgitude from the International Reference Meridian and height in meters above an ellipsoid based on the given datum. The datum in turn is based on a reference ellipsoid and tied to geodetic survey reference points.

Modern geodesy is generally based on the WGS84 datum (as used for instance by GPS systems), but previously various other reference ellipsoids and datum references were used.

The UK Ordnance Survey National Grid References are still based on the otherwise historical OSGB36 datum, q.v. "A Guide to Coordinate Systems in Great Britain", Section 6.

Version: 24.01.25

Classes
| Transform Helmert transformation.
| Datum Ellipsoid and transform parameters for an earth model.

Variables
| __all__ = `_ALL_LAZY.datums`
| Transforms = `Transforms.OSGB36: Transform(name='OSGB36', tx=-4`...`` Some pre-defined Transforms, all lazily instantiated.
| Datums = `Datums.OSGB36: Datum(name='OSGB36', ellipsoid=Ellipso`...`` Some pre-defined Datums, all lazily instantiated.
| Datums.BD72 Datum(name='BD72', ellipsoid=Ellipsoids.Intl1924, transform=Transforms.BD72)
| Datums.DHDN Datum(name='DHDN', ellipsoid=Ellipsoids.Bessel1841, transform=Transforms.DHDN)
| Datums.ED50 Datum(name='ED50', ellipsoid=Ellipsoids.Intl1924, transform=Transforms.ED50)
| Datums.GDA2020 Datum(name='GDA2020', ellipsoid=Ellipsoids.GRS80, transform=Transforms.WGS84)
| Datums.GRS80 Datum(name='GRS80', ellipsoid=Ellipsoids.GRS80, transform=Transforms.WGS84)
| Datums.Irl1975 Datum(name='Irl1975', ellipsoid=Ellipsoids.AiryModified, transform=Transforms.Irl1975)
| Datums.Krassovski1940 Datum(name='Krassovski1940', ellipsoid=Ellipsoids.Krassovski1940, transform=Transforms.Krassovski1940)
| Datums.Krassowsky1940 Datum(name='Krassowsky1940', ellipsoid=Ellipsoids.Krassowsky1940, transform=Transforms.Krassowsky1940)
| Datums.MGI Datum(name='MGI', ellipsoid=Ellipsoids.Bessel1841, transform=Transforms.MGI)
| Datums.NAD27 Datum(name='NAD27', ellipsoid=Ellipsoids.Clarke1866, transform=Transforms.NAD27)
| Datums.NAD83 Datum(name='NAD83', ellipsoid=Ellipsoids.GRS80, transform=Transforms.NAD83)
| Datums.NTF Datum(name='NTF', ellipsoid=Ellipsoids.Clarke1880IGN, transform=Transforms.NTF)
| Datums.OSGB36 Datum(name='OSGB36', ellipsoid=Ellipsoids.Airy1830, transform=Transforms.OSGB36)
| Datums.Potsdam Datum(name='Potsdam', ellipsoid=Ellipsoids.Bessel1841, transform=Transforms.Bessel1841)
| Datums.Sphere Datum(name='Sphere', ellipsoid=Ellipsoids.Sphere, transform=Transforms.WGS84)
| Datums.TokyoJapan Datum(name='TokyoJapan', ellipsoid=Ellipsoids.Bessel1841, transform=Transforms.TokyoJapan)
| Datums.WGS72 Datum(name='WGS72', ellipsoid=Ellipsoids.WGS72, transform=Transforms.WGS72)
| Datums.WGS84 Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Transforms.WGS84)
| Transforms.BD72 Transform(name='BD72', tx=106.86863, ty=-52.29778, tz=103.72389, rx=-0, ry=-0, rz=-0.00001, s=1.2727, s1=1, sx=-0.33657, sy=-0.45696, sz=-1.84218)
| Transforms.Bessel1841 Transform(name='Bessel1841', tx=-582, ty=-105, tz=-414, rx=-0.00001, ry=-0, rz=0.00001, s=-8.3, s1=0.99999, sx=-1.04, sy=-0.35, sz=3.08)
| Transforms.Clarke1866 Transform(name='Clarke1866', tx=8, ty=-160, tz=-176, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)
| Transforms.DHDN Transform(name='DHDN', tx=-591.28, ty=-81.35, tz=-396.39, rx=0.00001, ry=-0, rz=-0.00001, s=-9.82, s1=0.99999, sx=1.477, sy=-0.0736, sz=-1.458)
| Transforms.DHDNE Transform(name='DHDNE', tx=-612.4, ty=-77, tz=-440.2, rx=0, ry=-0, rz=0.00001, s=-2.55, s1=1, sx=0.054, sy=-0.057, sz=2.797)
| Transforms.DHDNW Transform(name='DHDNW', tx=-598.1, ty=-73.7, tz=-418.2, rx=-0, ry=-0, rz=0.00001, s=-6.7, s1=0.99999, sx=-0.202, sy=-0.045, sz=2.455)
| Transforms.ED50 Transform(name='ED50', tx=89.5, ty=93.8, tz=123.1, rx=0, ry=0, rz=0, s=-1.2, s1=1, sx=0, sy=0, sz=0.156)
| Transforms.Identity Transform(name='Identity', tx=0, ty=0, tz=0, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)
| Transforms.Irl1965 Transform(name='Irl1965', tx=-482.53, ty=130.596, tz=-564.557, rx=0.00001, ry=0, rz=0, s=-8.15, s1=0.99999, sx=1.042, sy=0.214, sz=0.631)
| Transforms.Irl1975 Transform(name='Irl1975', tx=-482.53, ty=130.596, tz=-564.557, rx=0.00001, ry=0, rz=0, s=-8.15, s1=0.99999, sx=1.042, sy=0.214, sz=0.631)
| Transforms.Krassovski1940 Transform(name='Krassovski1940', tx=-24, ty=123, tz=94, rx=-0, ry=0, rz=0, s=-2.423, s1=1, sx=-0.02, sy=0.26, sz=0.13)
| Transforms.Krassowsky1940 Transform(name='Krassowsky1940', tx=-24, ty=123, tz=94, rx=-0, ry=0, rz=0, s=-2.423, s1=1, sx=-0.02, sy=0.26, sz=0.13)
| Transforms.MGI Transform(name='MGI', tx=-577.326, ty=-90.129, tz=-463.92, rx=0.00002, ry=0.00001, rz=0.00003, s=-2.423, s1=1, sx=5.137, sy=1.474, sz=5.297)
| Transforms.NAD27 Transform(name='NAD27', tx=8, ty=-160, tz=-176, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)
| Transforms.NAD83 Transform(name='NAD83', tx=1.004, ty=-1.91, tz=-0.515, rx=0, ry=0, rz=0, s=-0.0015, s1=1, sx=0.0267, sy=0.00034, sz=0.011)
| Transforms.NTF Transform(name='NTF', tx=-168, ty=-60, tz=320, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)
| Transforms.OSGB36 Transform(name='OSGB36', tx=-446.448, ty=125.157, tz=-542.06, rx=-0, ry=-0, rz=-0, s=20.4894, s1=1.00002, sx=-0.1502, sy=-0.247, sz=-0.8421)
| Transforms.TokyoJapan Transform(name='TokyoJapan', tx=148, ty=-507, tz=-685, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)
| Transforms.WGS72 Transform(name='WGS72', tx=0, ty=0, tz=-4.5, rx=0, ry=0, rz=0, s=-0.22, s1=1, sx=0, sy=0, sz=0.554)
| Transforms.WGS84 Transform(name='WGS84', tx=0, ty=0, tz=0, rx=0, ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0) # .isunity

Variables Details

  ### Transforms Some pre-defined Transforms, all lazily instantiated. Value:
      Transforms.OSGB36: Transform(name='OSGB36', tx=-446.448, ty=125.157, t
      z=-542.06, rx=-0, ry=-0, rz=-0, s=20.4894, s1=1.00002, sx=-0.1502, sy=
      -0.247, sz=-0.8421),
      Transforms.WGS84: Transform(name='WGS84', tx=0, ty=0, tz=0, rx=0, ry=0
      , rz=0, s=0, s1=1, sx=0, sy=0, sz=0),
      Transforms.Identity: Transform(name='Identity', tx=0, ty=0, tz=0, rx=0
      , ry=0, rz=0, s=0, s1=1, sx=0, sy=0, sz=0)

  ### Datums Some pre-defined Datums, all lazily instantiated. Value:
      Datums.OSGB36: Datum(name='OSGB36', ellipsoid=Ellipsoids.Airy1830, tra
      nsform=Transforms.OSGB36),
      Datums.GRS80: Datum(name='GRS80', ellipsoid=Ellipsoids.GRS80, transfor
      m=Transforms.WGS84),
      Datums.WGS84: Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transfor
      m=Transforms.WGS84),
      Datums.Sphere: Datum(name='Sphere', ellipsoid=Ellipsoids.Sphere, trans
      form=Transforms.WGS84)