def geo_mask(self):
"""Masking the space pixels from geometry info."""
cfac = np.uint32(self.proj_info['CFAC'])
lfac = np.uint32(self.proj_info['LFAC'])
coff = np.float32(self.proj_info['COFF'])
loff = np.float32(self.proj_info['LOFF'])
nlines = int(self.data_info['number_of_lines'])
ncols = int(self.data_info['number_of_columns'])
# count starts at 1
local_coff = 1
local_loff = (self.total_segments - self.segment_number) * nlines + 1
xmax, ymax = get_geostationary_angle_extent(self.area)
pixel_cmax = np.rad2deg(xmax) * cfac * 1.0 / 2**16
pixel_lmax = np.rad2deg(ymax) * lfac * 1.0 / 2**16
def ellipse(line, col):
return ((line / pixel_lmax) ** 2) + ((col / pixel_cmax) ** 2) <= 1
cols_idx = da.arange(-(coff - local_coff),
ncols - (coff - local_coff),
dtype=np.float, chunks=CHUNK_SIZE)
lines_idx = da.arange(nlines - (loff - local_loff),
-(loff - local_loff),
-1,
dtype=np.float, chunks=CHUNK_SIZE)
return ellipse(lines_idx[:, None], cols_idx[None, :])
def geo_mask(self):
"""Masking the space pixels from geometry info."""
cfac = np.uint32(self.proj_info['CFAC'])
lfac = np.uint32(self.proj_info['LFAC'])
coff = np.float32(self.proj_info['COFF'])
loff = np.float32(self.proj_info['LOFF'])
nlines = int(self.data_info['number_of_lines'])
ncols = int(self.data_info['number_of_columns'])
# count starts at 1
local_coff = 1
local_loff = (self.total_segments - self.segment_number) * nlines + 1
xmax, ymax = get_geostationary_angle_extent(self.area)
pixel_cmax = np.rad2deg(xmax) * cfac * 1.0 / 2**16
pixel_lmax = np.rad2deg(ymax) * lfac * 1.0 / 2**16
def ellipse(line, col):
return ((line / pixel_lmax) ** 2) + ((col / pixel_cmax) ** 2) <= 1
cols_idx = da.arange(-(coff - local_coff),
ncols - (coff - local_coff),
dtype=np.float, chunks=CHUNK_SIZE)
lines_idx = da.arange(nlines - (loff - local_loff),
-(loff - local_loff),
-1,
dtype=np.float, chunks=CHUNK_SIZE)
return ellipse(lines_idx[:, None], cols_idx[None, :])
def test_get_geostationary_angle_extent(self):
"""Get max geostationary angles."""
geos_area = mock.MagicMock()
geos_area.proj_dict = {'a': 6378169.00,
'b': 6356583.80,
'h': 35785831.00}
expected = (0.15185342867090912, 0.15133555510297725)
np.testing.assert_allclose(expected,
hf.get_geostationary_angle_extent(geos_area))
geos_area.proj_dict = {'a': 1000.0,
'b': 1000.0,
'h': np.sqrt(2) * 1000.0 - 1000.0}
expected = (np.deg2rad(45), np.deg2rad(45))
np.testing.assert_allclose(expected,
hf.get_geostationary_angle_extent(geos_area))
def test_get_geostationary_angle_extent(self):
"""Get max geostationary angles."""
geos_area = mock.MagicMock()
del geos_area.crs
geos_area.proj_dict = {
'proj': 'geos',
'sweep': 'x',
'lon_0': -89.5,
'a': 6378169.00,
'b': 6356583.80,
'h': 35785831.00,
'units': 'm'
}
expected = (0.15185342867090912, 0.15133555510297725)
np.testing.assert_allclose(
expected, hf.get_geostationary_angle_extent(geos_area))
geos_area.proj_dict['a'] = 1000.0
geos_area.proj_dict['b'] = 1000.0
geos_area.proj_dict['h'] = np.sqrt(2) * 1000.0 - 1000.0
expected = (np.deg2rad(45), np.deg2rad(45))
np.testing.assert_allclose(
expected, hf.get_geostationary_angle_extent(geos_area))
geos_area.proj_dict = {
'proj': 'geos',
'sweep': 'x',
'lon_0': -89.5,
'ellps': 'GRS80',
'h': 35785831.00,
'units': 'm'
}
expected = (0.15185277703584374, 0.15133971368991794)
np.testing.assert_allclose(
expected, hf.get_geostationary_angle_extent(geos_area))
def _get_area_def_uniform_sampling(self, lon0, channel):
"""Get area definition with uniform sampling"""
logger.debug('Computing area definition')
if lon0 is not None:
# Define proj4 projection parameters
proj_dict = {
'a': EQUATOR_RADIUS,
'b': POLE_RADIUS,
'lon_0': lon0,
'h': ALTITUDE,
'proj': 'geos',
'units': 'm'
}
# Calculate maximum scanning angles
xmax, ymax = get_geostationary_angle_extent(
namedtuple('area', ['proj_dict'])(proj_dict))
# Derive area extent using small angle approximation (maximum
# scanning angle is ~8.6 degrees)
llx, lly, urx, ury = ALTITUDE * np.array(
[-xmax, -ymax, xmax, ymax])
area_extent = [llx, lly, urx, ury]
# Original image is oversampled. Create pyresample area definition
# with uniform sampling in N-S and E-W direction
if self._is_vis(channel):
sampling = SAMPLING_NS_VIS
else:
sampling = SAMPLING_NS_IR
pix_size = ALTITUDE * sampling
area_def = pyresample.geometry.AreaDefinition(
area_id='goes_geos_uniform',
name='{} geostationary projection (uniform sampling)'.format(
self.platform_name),
proj_id='goes_geos_uniform',
proj_dict=proj_dict,
x_size=np.rint((urx - llx) / pix_size).astype(int),
y_size=np.rint((ury - lly) / pix_size).astype(int),
area_extent=area_extent)
return area_def
else:
return None
