def to_cartesian(self):
"""
Converts WGS84 geodetic coordinates to 3D rectangular (geocentric)
cartesian coordinates.
"""
xyz = erfa.gd2gc(getattr(erfa, self._ellipsoid), self.lon, self.lat,
self.height)
return CartesianRepresentation(xyz, xyz_axis=-1, copy=False)
def __init__(self, longitude, latitude, altitude):
# site terrestrial coordinates (WGS84)
self.latnd, self.latnm, self.slatn = map(int, latitude.split(':'))
self.lonwd, self.lonwm, self.slonw = map(int, longitude.split(':'))
self.hm = altitude
# transform to geocentric
self.phi = erfa.af2a(self.latnd, self.latnm, self.slatn)
self.elon = erfa.af2a(self.lonwd, self.lonwm, self.slonw)
self.xyz = erfa.gd2gc(1, self.elon, self.phi, self.hm)
self.u = math.hypot(self.xyz[0], self.xyz[1])
self.v = self.xyz[2]
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)
at sea level, on 2006 January 15 at 21:24:37.5 UTC
requires the time in all other supported time scales''')
# site terrestrial coordinates (WGS84)
latnd = +19
latnm = 28
slatn = 52.5
lonwd = -155
lonwm = 55
slonw = 59.6
hm = 0.
# transform to geocentric
phi = erfa.af2a(np.array([[latnd, latnm, slatn]]))
elon = erfa.af2a(np.array([[lonwd, lonwm, slonw]]))
xyz = erfa.gd2gc(1, elon, phi, np.array([hm]))[0]
u = np.array([math.hypot(xyz[0], xyz[1])])
v = np.array([xyz[2]])
# UTC date and time
iy = np.array([2006])
mo = np.array([1])
d = np.array([15])
ih = np.array([21])
im = np.array([24])
sec = np.array([37.5])
# transform into intenal format
utc1, utc2 = erfa.dtf2d("UTC", iy,mo,d,ih,im,sec)
# UT1-UTC from IERS
at sea level, on 2006 January 15 at 21:24:37.5 UTC requires the time in all other supported time scales''') # site terrestrial coordinates (WGS84) latnd = +19 latnm = 28 slatn = 52.5 lonwd = -155 lonwm = 55 slonw = 59.6 hm = 0. # transform to geocentric phi = erfa.af2a(latnd, latnm, slatn) elon = erfa.af2a(lonwd, lonwm, slonw) xyz = erfa.gd2gc(1, elon, phi, hm) u = math.hypot(xyz[0], xyz[1]) v = xyz[2] # UTC date and time iy = 2006 mo = 1 d = 15 ih = 21 im = 24 sec = 37.5 # transform into intenal format utc1, utc2 = erfa.dtf2d(iy, mo, d, ih, im, sec, "UTC") # UT1-UTC from IERS
at sea level, on 2006 January 15 at 21:24:37.5 UTC requires the time in all other supported time scales''') # site terrestrial coordinates (WGS84) latnd = +19 latnm = 28 slatn = 52.5 lonwd = -155 lonwm = 55 slonw = 59.6 hm = 0. # transform to geocentric phi = erfa.af2a(latnd, latnm, slatn) elon = erfa.af2a(lonwd, lonwm, slonw) xyz = erfa.gd2gc(1, elon, phi, hm) u = math.hypot(xyz[0], xyz[1]) v = xyz[2] # UTC date and time iy = 2006 mo = 1 d = 15 ih = 21 im = 24 sec = 37.5 # transform into intenal format utc1, utc2 = erfa.dtf2d(iy,mo,d,ih,im,sec, "UTC") # UT1-UTC from IERS
