def tangent_point_coordinates(self,
lon_lin,
lat_lin,
flight_alt=14,
cut_height=12):
"""
Computes coordinates of tangent points given coordinates of flight path.
Args:
lon_lin: longitudes of flight path
lat_lin: latitudes of flight path
flight_alt: altitude of aircraft (scalar or numpy array)
cut_height: altitude of tangent points
Returns: List of tuples of longitude/latitude coordinates
"""
lins = list(zip(lon_lin[0:-1], lon_lin[1:], lat_lin[0:-1],
lat_lin[1:]))
lins = [(x0 * np.cos(np.deg2rad(np.mean([y0, y1]))),
x1 * np.cos(np.deg2rad(np.mean([y0, y1]))), y0, y1)
for x0, x1, y0, y1 in lins]
direction = [(x1 - x0, y1 - y0) for x0, x1, y0, y1 in lins]
direction = [(_x / np.hypot(_x, _y), _y / np.hypot(_x, _y))
for _x, _y in direction]
los = [
rotate_point(point, -self.dsbObsAngleAzimuth.value())
for point in direction
]
los.append(los[-1])
if isinstance(flight_alt, (collections.abc.Sequence, np.ndarray)):
dist = [(np.sqrt(
max((EARTH_RADIUS + a)**2 -
(EARTH_RADIUS + cut_height)**2, 0)) / 110.)
for a in flight_alt[:-1]]
dist.append(dist[-1])
else:
dist = (np.sqrt((EARTH_RADIUS + flight_alt)**2 -
(EARTH_RADIUS + cut_height)**2) / 110.)
tp_dir = (np.array(los).T * dist).T
tps = [(x0 + tp_x, y0 + tp_y, y0)
for ((x0, x1, y0, y1), (tp_x, tp_y)) in zip(lins, tp_dir)]
tps = [(x0 / np.cos(np.deg2rad(yp)), y0) for (x0, y0, yp) in tps]
return tps
def create_hexagon(center_lat, center_lon, radius, angle=0.):
coords_0 = (radius, 0.)
coords_cart_0 = [rotate_point(coords_0, angle=0. + angle),
rotate_point(coords_0, angle=60. + angle),
rotate_point(coords_0, angle=120. + angle),
rotate_point(coords_0, angle=180. + angle),
rotate_point(coords_0, angle=240. + angle),
rotate_point(coords_0, angle=300. + angle),
rotate_point(coords_0, angle=360. + angle)]
coords_sphere_rot = [
(center_lat + (vec[0] / 110.),
center_lon + (vec[1] / (110. * np.cos(np.deg2rad((vec[0] / 110.) + center_lat)))))
for vec in coords_cart_0]
return coords_sphere_rot
def direction_coordinates(self, lon_lin, lat_lin):
"""
Computes coordinates of tangent points given coordinates of flight path.
Args:
lon_lin: longitudes of flight path
lat_lin: latitudes of flight path
flight_alt: altitude of aircraft (scalar or numpy array)
cut_height: altitude of tangent points
Returns: List of tuples of longitude/latitude coordinates
"""
lins = list(zip(lon_lin[0:-1], lon_lin[1:], lat_lin[0:-1],
lat_lin[1:]))
lins = [(x0 * np.cos(np.deg2rad(np.mean([y0, y1]))),
x1 * np.cos(np.deg2rad(np.mean([y0, y1]))), y0, y1)
for x0, x1, y0, y1 in lins]
lens = [np.hypot(x1 - x0, y1 - y0) * 110. for x0, x1, y0, y1 in lins]
lins = [_x for _x, _l in zip(lins, lens) if _l > 10]
direction = [(0.5 * (x0 + x1), 0.5 * (y0 + y1), x1 - x0, y1 - y0)
for x0, x1, y0, y1 in lins]
direction = [(_u, _v, _x / np.hypot(_x, _y), _y / np.hypot(_x, _y))
for _u, _v, _x, _y in direction]
los = [
rotate_point(point[2:], -self.dsbObsAngleAzimuth.value())
for point in direction
]
dist = 1.
tp_dir = (np.array(los).T * dist).T
tps = [(x0, y0, x0 + tp_x, y0 + tp_y)
for ((x0, y0, _, _), (tp_x, tp_y)) in zip(direction, tp_dir)]
tps = [[(x0 / np.cos(np.deg2rad(y0)), y0),
(x1 / np.cos(np.deg2rad(y0)), y1)] for (x0, y0, x1, y1) in tps]
return tps
def test_rotate_point(self):
assert utils.rotate_point([0, 0], 0) == (0.0, 0.0)
assert utils.rotate_point([0, 0], 180) == (0.0, 0.0)
assert utils.rotate_point([1, 0], 0) == (1.0, 0.0)
assert utils.rotate_point([100, 90], 90) == (-90, 100)
