Package pygeodesy :: Module trf
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Module trf

Terrestrial Reference Frame (TRF) classes RefFrame, registry RefFrames and TRFError.

Transcribed from Chris Veness' (C) 2006-2019 JavaScript originals latlon-ellipsoidal-referenceframe.js and latlon-ellipsoidal-referenceframe-txparams.js.

Modern geodetic reference frames: a latitude/longitude point defines a geographic location on, above or below the earth’s surface, measured in degrees from the equator and the International Reference Meridian (IRM) and metres above the ellipsoid within a given Terrestrial Reference Frame at a given epoch.

This is scratching the surface of complexities involved in high precision geodesy, but may be of interest and/or value to those with less demanding requirements. More information here and here.

Note that ITRF solutions do not directly use an ellipsoid, but are specified by Cartesian coordinates. The GRS80 ellipsoid is recommended for transformations to geographical coordinates.

Note WGS84(G730/G873/G1150) are coincident with ITRF at 10-centimetre level, see also here. WGS84(G1674) and ITRF20014 / ITRF2008 ‘are likely to agree at the centimeter level’, see also QPS/QINSy.


Version: 19.10.12

Classes
  TRFError
Terrestrial Reference Frame (TRF) or RefFrame conversion issue.
  RefFrame
Terrestrial Reference Frame (TRF) parameters.
Functions
 
date2epoch(year, month, day)
Return the reference frame epoch for a calendar day.
Variables
  __all__ = _ALL_LAZY.trf
  RefFrames = RefFrames.ETRF2000: RefFrame(name='ETRF2000', epoc...
Registered reference frames.
  RefFrames.ETRF2000
RefFrame(name='ETRF2000', epoch=2005.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.GDA94
RefFrame(name='GDA94', epoch=1994.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF2000
RefFrame(name='ITRF2000', epoch=1997.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF2005
RefFrame(name='ITRF2005', epoch=2000.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF2008
RefFrame(name='ITRF2008', epoch=2005.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF2014
RefFrame(name='ITRF2014', epoch=2010.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF91
RefFrame(name='ITRF91', epoch=1988.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.ITRF93
RefFrame(name='ITRF93', epoch=1988.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.NAD83
RefFrame(name='NAD83', epoch=1997.0, ellipsoid=Ellipsoid(name='GRS80')
  RefFrames.WGS84g1150
RefFrame(name='WGS84g1150', epoch=2001.0, ellipsoid=Ellipsoid(name='WGS84')
  RefFrames.WGS84g1674
RefFrame(name='WGS84g1674', epoch=2005.0, ellipsoid=Ellipsoid(name='WGS84')
  RefFrames.WGS84g1762
RefFrame(name='WGS84g1762', epoch=2005.0, ellipsoid=Ellipsoid(name='WGS84')
Function Details

date2epoch(year, month, day)

 

Return the reference frame epoch for a calendar day.

Parameters:
  • year - Year of the date (scalar).
  • month - Month in the year (scalar, 1..12).
  • day - Day in the month (scalar, 1..31).
Returns:
Epoch, the fractional year (float).
Raises:
  • TRFError - Invalid year, month or day.

Note: Any year is considered a leap year, i.e. having 29 days in February.


Variables Details

RefFrames

Registered reference frames.

Value:
RefFrames.ETRF2000: RefFrame(name='ETRF2000', epoch=2005.0, ellipsoid=\
Ellipsoid(name='GRS80'),
RefFrames.GDA94: RefFrame(name='GDA94', epoch=1994.0, ellipsoid=Ellips\
oid(name='GRS80'),
RefFrames.ITRF2000: RefFrame(name='ITRF2000', epoch=1997.0, ellipsoid=\
Ellipsoid(name='GRS80'),
RefFrames.ITRF2005: RefFrame(name='ITRF2005', epoch=2000.0, ellipsoid=\
Ellipsoid(name='GRS80'),
...