def __init_fixed_grid_data(self):
""" Calculate the fixed grid coordinates for flashes, groups, and events
and save them to self.dataset as new variables named
event_x, event_y, group_x, group_y, flash_x, flash_y
"""
nadir_lon = self.dataset.lon_field_of_view.data
ellipse_rev = self.ellipse_rev
if ellipse_rev < 0:
log.info("Inferring lightning ellipsoid from GLM product time")
pt = self.dataset.product_time.dt
date = datetime(pt.year, pt.month, pt.day,
pt.hour, pt.minute, pt.second)
ellipse_rev = ltg_ellpse_rev(date)
log.info("Using lightning ellipsoid rev {0}".format(ellipse_rev))
event_x, event_y = ltg_ellps_lon_lat_to_fixed_grid(
self.dataset.event_lon.data, self.dataset.event_lat.data,
nadir_lon, ellipse_rev)
self.dataset['event_x'] = xr.DataArray(event_x, dims=[self.ev_dim,])
self.dataset['event_y'] = xr.DataArray(event_y, dims=[self.ev_dim,])
group_x, group_y = ltg_ellps_lon_lat_to_fixed_grid(
self.dataset.group_lon.data, self.dataset.group_lat.data,
nadir_lon, ellipse_rev)
self.dataset['group_x'] = xr.DataArray(group_x, dims=[self.gr_dim,])
self.dataset['group_y'] = xr.DataArray(group_y, dims=[self.gr_dim,])
flash_x, flash_y = ltg_ellps_lon_lat_to_fixed_grid(
self.dataset.flash_lon.data, self.dataset.flash_lat.data,
nadir_lon, ellipse_rev)
self.dataset['flash_x'] = xr.DataArray(flash_x, dims=[self.fl_dim,])
self.dataset['flash_y'] = xr.DataArray(flash_y, dims=[self.fl_dim,])
def test_ellipse_at_launch():
# This example based on the ellipsoid *at launch* through the first
# revision to the ellipsoid
date = datetime(2018, 1, 1)
ellipse_rev = ltg_ellpse_rev(date)
goes_lon = -75.0
test_lon = -110., -110., -57., -57.
test_lat = 42., -45., 46., -41.
fix_testx = np.asarray((-7.072352765696357, -6.693857076039071, 3.593939139528318, 3.945876828443619))*1e4
fix_testy = np.asarray((1.106891557528977, -1.163584191758841, 1.199674272612177, -1.105394721298256))*1e5
fix_x, fix_y = ltg_ellps_lon_lat_to_fixed_grid(test_lon, test_lat,
goes_lon, ellipse_rev)
# Differences are < 0.5 microradians
assert np.allclose(fix_y*1e6, fix_testy)
assert np.allclose(fix_x*1e6, fix_testx)
def test_ellipse_revJ_ellipse():
date = datetime(2030, 12, 31)
# re, rp = ltg_ellps_radii(date)
ellipse_rev = ltg_ellpse_rev(date)
# This example based on the ellipsoid *at launch*
goes_lon = -75.0
test_lon = -110., -110., -57., -57.
test_lat = 42., -45., 46., -41.
fix_testx = np.asarray([-70709.97522351, -66926.99992007, 35933.3006532, 39450.81169228])
fix_testy = np.asarray([ 110667.78669847, -116338.15403498, 119946.98040115, -110517.06815844])
fix_x, fix_y = ltg_ellps_lon_lat_to_fixed_grid(test_lon, test_lat,
goes_lon, ellipse_rev)
fix_x *= 1e6
fix_y *= 1e6
# Differences are < 0.5 microradians
assert np.allclose(fix_y, fix_testy)
assert np.allclose(fix_x, fix_testx)