def _compute_missing_lonlat(self, missed_utcs):
"""compute lon lat values using pyorbital"""
tic = datetime.datetime.now()
scan_rate = datetime.timedelta(milliseconds=1/self.scan_freq).total_seconds()
sgeom = avhrr_gac(missed_utcs.astype(datetime.datetime),
self.scan_points, frequency=scan_rate)
t0 = missed_utcs[0].astype(datetime.datetime)
s_times = sgeom.times(t0)
tle1, tle2 = self.get_tle_lines()
rpy = self.get_attitude_coeffs()
pixels_pos = compute_pixels((tle1, tle2), sgeom, s_times, rpy)
pos_time = get_lonlatalt(pixels_pos, s_times)
missed_lons, missed_lats = pos_time[:2]
pixels_per_line = self.lats.shape[1]
missed_lons = missed_lons.reshape(-1, pixels_per_line)
missed_lats = missed_lats.reshape(-1, pixels_per_line)
toc = datetime.datetime.now()
LOG.warning("Computation of geolocation: %s", str(toc - tic))
return missed_lons, missed_lats
def compute_lonlat(self, width, utcs=None, clock_drift_adjust=True):
"""Compute lat/lon coordinates.
Args:
width: Number of coordinates per scanlines
utcs: Scanline timestamps
clock_drift_adjust: If True, adjust clock drift.
"""
tle1, tle2 = self.get_tle_lines()
scan_points = np.arange(3.5, 2048, 5)
if utcs is None:
utcs = self.get_times()
# adjusting clock for drift
tic = datetime.datetime.now()
if clock_drift_adjust:
from pygac.clock_offsets_converter import get_offsets
try:
offset_times, clock_error = get_offsets(self.spacecraft_name)
except KeyError:
LOG.info("No clock drift info available for %s",
self.spacecraft_name)
else:
offset_times = np.array(offset_times, dtype='datetime64[ms]')
offsets = np.interp(utcs.astype(np.uint64),
offset_times.astype(np.uint64),
clock_error)
utcs -= (offsets * 1000).astype('timedelta64[ms]')
t = utcs[0].astype(datetime.datetime)
if "constant_yaw_attitude_error" in self.head.dtype.fields:
rpy = np.deg2rad([
self.head["constant_roll_attitude_error"] / 1e3,
self.head["constant_pitch_attitude_error"] / 1e3,
self.head["constant_yaw_attitude_error"] / 1e3
])
else:
rpy = [0, 0, 0]
LOG.info("Using rpy: %s", str(rpy))
from pyorbital.geoloc_instrument_definitions import avhrr_gac
from pyorbital.geoloc import compute_pixels, get_lonlatalt
sgeom = avhrr_gac(utcs.astype(datetime.datetime), scan_points, 55.385)
s_times = sgeom.times(t)
pixels_pos = compute_pixels((tle1, tle2), sgeom, s_times, rpy)
pos_time = get_lonlatalt(pixels_pos, s_times)
toc = datetime.datetime.now()
LOG.warning("Computation of geolocation: %s", str(toc - tic))
lons, lats = pos_time[:2]
return lons.reshape(-1, width), lats.reshape(-1, width)
def compute_lonlat(self, width, utcs=None, clock_drift_adjust=True):
"""Compute lat/lon coordinates.
Args:
width: Number of coordinates per scanlines
utcs: Scanline timestamps
clock_drift_adjust: If True, adjust clock drift.
"""
if utcs is None:
utcs = self.get_times()
# adjusting clock for drift
tic = datetime.datetime.now()
if clock_drift_adjust:
from pygac.clock_offsets_converter import get_offsets
try:
offset_times, clock_error = get_offsets(self.spacecraft_name)
except KeyError:
LOG.info("No clock drift info available for %s",
self.spacecraft_name)
else:
offset_times = np.array(offset_times, dtype='datetime64[ms]')
offsets = np.interp(utcs.astype(np.uint64),
offset_times.astype(np.uint64),
clock_error)
utcs = utcs - (offsets * 1000).astype('timedelta64[ms]')
t = utcs[0].astype(datetime.datetime)
if "constant_yaw_attitude_error" in self.head.dtype.fields:
rpy = np.deg2rad([
self.head["constant_roll_attitude_error"] / 1e3,
self.head["constant_pitch_attitude_error"] / 1e3,
self.head["constant_yaw_attitude_error"] / 1e3
])
else:
try:
# This needs to be checked thoroughly first
# rpy_spacecraft = rpy_coeffs[self.spacecraft_name]
# rpy = [rpy_spacecraft['roll'],
# rpy_spacecraft['pitch'],
# rpy_spacecraft['yaw']]
# LOG.debug("Using static attitude correction")
raise KeyError
except KeyError:
LOG.debug("Not applying attitude correction")
rpy = [0, 0, 0]
LOG.info("Using rpy: %s", str(rpy))
from pyorbital.geoloc_instrument_definitions import avhrr_gac
from pyorbital.geoloc import compute_pixels, get_lonlatalt
# TODO: Are we sure all satellites have this scan width in degrees ?
sgeom = avhrr_gac(utcs.astype(datetime.datetime), self.scan_points,
55.385)
s_times = sgeom.times(t)
tle1, tle2 = self.get_tle_lines()
pixels_pos = compute_pixels((tle1, tle2), sgeom, s_times, rpy)
pos_time = get_lonlatalt(pixels_pos, s_times)
toc = datetime.datetime.now()
LOG.warning("Computation of geolocation: %s", str(toc - tic))
lons, lats = pos_time[:2]
return lons.reshape(-1, width), lats.reshape(-1, width)