def from_geodetic(cls, lon, lat, height=0., ellipsoid=None):
"""
Location on Earth, initialized from geodetic coordinates.
Parameters
----------
lon : `~astropy.coordinates.Longitude` or float
Earth East longitude. Can be anything that initialises an
`~astropy.coordinates.Angle` object (if float, in degrees).
lat : `~astropy.coordinates.Latitude` or float
Earth latitude. Can be anything that initialises an
`~astropy.coordinates.Latitude` object (if float, in degrees).
height : `~astropy.units.Quantity` or float, optional
Height above reference ellipsoid (if float, in meters; default: 0).
ellipsoid : str, optional
Name of the reference ellipsoid to use (default: 'WGS84').
Available ellipsoids are: 'WGS84', 'GRS80', 'WGS72'.
Raises
------
astropy.units.UnitsError
If the units on ``lon`` and ``lat`` are inconsistent with angular
ones, or that on ``height`` with a length.
ValueError
If ``lon``, ``lat``, and ``height`` do not have the same shape, or
if ``ellipsoid`` is not recognized as among the ones implemented.
Notes
-----
For the conversion to geocentric coordinates, the ERFA routine
``gd2gc`` is used. See https://github.com/liberfa/erfa
"""
ellipsoid = _check_ellipsoid(ellipsoid, default=cls._ellipsoid)
# We use Angle here since there is no need to wrap the longitude -
# gd2gc will just take cos/sin anyway. And wrapping might fail
# on readonly input.
lon = Angle(lon, u.degree, copy=False)
lat = Latitude(lat, u.degree, copy=False)
# don't convert to m by default, so we can use the height unit below.
if not isinstance(height, u.Quantity):
height = u.Quantity(height, u.m, copy=False)
# get geocentric coordinates. Have to give one-dimensional array.
xyz = erfa.gd2gc(getattr(erfa, ellipsoid),
lon.to_value(u.radian),
lat.to_value(u.radian),
height.to_value(u.m))
self = xyz.ravel().view(cls._location_dtype,
cls).reshape(xyz.shape[:-1])
self._unit = u.meter
self._ellipsoid = ellipsoid
return self.to(height.unit)
def lla2itrs(lla):
"""
uses ERFA's geodetic to geocentric function and the WGS84 ellipsoid parameters
Input:
lla is assumed to be a numpy array of dimension [3] or [n,3], where 3 is the lon (radians),lat (radians),
height (meters) of the geodetic coordinates of n different sets of coordinates
Output:
xyz is assumed to be a numpy array of dimension [3] or [n,3], where 3 is the x,z,y cartesian coordinates in
meters of n different sets of coordinates
"""
lla = np.atleast_2d(lla)
xyz = np.array(gd2gc(1, lla[:, 0], lla[:, 1], lla[:, 2]), dtype=np.float64)
if xyz.size == 3:
xyz = xyz[0]
return xyz
def from_geodetic(cls, lon, lat, height=0., ellipsoid=None):
"""
Location on Earth, initialized from geodetic coordinates.
Parameters
----------
lon : `~astropy.coordinates.Longitude` or float
Earth East longitude. Can be anything that initialises an
`~astropy.coordinates.Angle` object (if float, in degrees).
lat : `~astropy.coordinates.Latitude` or float
Earth latitude. Can be anything that initialises an
`~astropy.coordinates.Latitude` object (if float, in degrees).
height : `~astropy.units.Quantity` or float, optional
Height above reference ellipsoid (if float, in meters; default: 0).
ellipsoid : str, optional
Name of the reference ellipsoid to use (default: 'WGS84').
Available ellipsoids are: 'WGS84', 'GRS80', 'WGS72'.
Raises
------
astropy.units.UnitsError
If the units on ``lon`` and ``lat`` are inconsistent with angular
ones, or that on ``height`` with a length.
ValueError
If ``lon``, ``lat``, and ``height`` do not have the same shape, or
if ``ellipsoid`` is not recognized as among the ones implemented.
Notes
-----
For the conversion to geocentric coordinates, the ERFA routine
``gd2gc`` is used. See https://github.com/liberfa/erfa
"""
ellipsoid = _check_ellipsoid(ellipsoid, default=cls._ellipsoid)
lon = Longitude(lon, u.degree, wrap_angle=180*u.degree, copy=False)
lat = Latitude(lat, u.degree, copy=False)
# don't convert to m by default, so we can use the height unit below.
if not isinstance(height, u.Quantity):
height = u.Quantity(height, u.m, copy=False)
# get geocentric coordinates. Have to give one-dimensional array.
xyz = erfa.gd2gc(getattr(erfa, ellipsoid),
lon.to_value(u.radian),
lat.to_value(u.radian),
height.to_value(u.m))
self = xyz.ravel().view(cls._location_dtype,
cls).reshape(xyz.shape[:-1])
self._unit = u.meter
self._ellipsoid = ellipsoid
return self.to(height.unit)
def site_location(elong, phi, height):
"""
Return site position vector in cartesian coordintate in ITRS system,
based on WGS84 reference ellipsoid
Parameter:
==========
elong, phi, height: double arrays of sites' geodetic cooradinates
Return:
=======
location: double array
"""
n = 1 # WGS84
# n = 2 GRS80
# n = 3 # WGS72
return erfa.gd2gc(n, elong, phi, height)
