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greglucas merged 1 commit into from
Jan 29, 2026
+58 −35
Merged

Lo l1b off angle #2636

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8 changes: 8 additions & 0 deletions imap_processing/lo/l1b/lo_l1b.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1313,6 +1313,14 @@ def set_pointing_bin(l1b_de: xr.Dataset) -> xr.Dataset:
lons = (lons + 360) % 360
# third column: latitude
lats = direction[:, 2]
# we want this relative to the pivot angle
# i.e. the off_angle is +/- 2 degrees from the pivot angle
lats = lats - (90 - l1b_de["pivot_angle"].values[0])
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@subagonsouth subagonsouth Jan 29, 2026

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I'm wondering if you really want to modify the lats here, or if it would make more sense to modify the lat_bins. The concern is that the off_angle values sort of lose the fact that they relative to the pivot angle. I would think that a user would want off_angle_bins to be in latitudinal degrees.

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@greglucas greglucas Jan 29, 2026

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I was also not sure, but I spoke with Lo yesterday and they want off_angle to be the range +/- 2, so relative to the pivot_angle no matter what the pivot_angle is. I agree this adds confusion though.

if np.any(lats < -2) or np.any(lats > 2):
logger.warning(
"Some latitude values are outside of the +/-2 degree range "
f"for off-angle binning. Range: ({np.min(lats)}, {np.max(lats)})"
)

# Define bin edges
# 3600 bins, 0.1° each
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85 changes: 50 additions & 35 deletions imap_processing/tests/lo/test_lo_l1b.py
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Original file line number Diff line number Diff line change
Expand Up @@ -833,44 +833,59 @@ def test_set_direction(mock_lo_instrument_pointing, imap_ena_sim_metakernel):
)


@patch(
"imap_processing.lo.l1b.lo_l1b.frame_transform",
return_value=np.array([[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]),
)
@patch(
"imap_processing.lo.l1b.lo_l1b.cartesian_to_latitudinal",
# Longitudes: -180 -> 180, 0 -> 0, 90 -> 90, 180 -> 180
# After shift to 0-360: 180, 0, 90, 180
return_value=np.array([[0, -180, -2], [0, 0, 0], [0, 90, 1], [0, 180, 2]]),
)
def test_pointing_bins(mock_cartesian_to_latitudinal, mock_frame_transform):
# Arrange
l1b_de = xr.Dataset(
{
"hae_x": ("epoch", [1, 1, 1, 1]),
"hae_y": ("epoch", [0, 0, 0, 0]),
"hae_z": ("epoch", [0, 0, 0, 0]),
},
coords={
"epoch": [
7.9794907049e17,
7.9794907153e17,
7.9794907254e17,
7.9794907354e17,
],
},
)
@pytest.mark.parametrize("pivot_angle", [75, 90, 105])
def test_pointing_bins(pivot_angle):
# Arrange - Mock returns depend on pivot_angle
# Calculate offset based on pivot angle: lats = lats - (90 - pivot_angle)
offset = 90 - pivot_angle

with (
patch(
"imap_processing.lo.l1b.lo_l1b.frame_transform",
return_value=np.array([[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]),
),
patch(
"imap_processing.lo.l1b.lo_l1b.cartesian_to_latitudinal",
# Adjust latitude values based on pivot angle offset
# Longitudes: -180 -> 180, 0 -> 0, 90 -> 90, 180 -> 180
# After shift to 0-360: 180, 0, 90, 180
return_value=np.array(
[
[0, -180, -2 + offset],
[0, 0, 0 + offset],
[0, 90, 1 + offset],
[0, 180, 2 + offset],
]
),
),
):
l1b_de = xr.Dataset(
{
"hae_x": ("epoch", [1, 1, 1, 1]),
"hae_y": ("epoch", [0, 0, 0, 0]),
"hae_z": ("epoch", [0, 0, 0, 0]),
},
coords={
"epoch": [
7.9794907049e17,
7.9794907153e17,
7.9794907254e17,
7.9794907354e17,
],
"pivot_angle": [pivot_angle],
},
)

expected_pointing_lats = np.array([0, 20, 30, 40])
# Longitude bins are now in 0-360 range after the shift
expected_pointing_lons = np.array([1800, 0, 900, 1800])
expected_pointing_lats = np.array([0, 20, 30, 40])
# Longitude bins are now in 0-360 range after the shift
expected_pointing_lons = np.array([1800, 0, 900, 1800])

# Act
l1b_de = set_pointing_bin(l1b_de)
# Act
l1b_de = set_pointing_bin(l1b_de)

# Assert
np.testing.assert_array_equal(l1b_de["off_angle_bin"], expected_pointing_lats)
np.testing.assert_array_equal(l1b_de["spin_bin"], expected_pointing_lons)
# Assert
np.testing.assert_array_equal(l1b_de["off_angle_bin"], expected_pointing_lats)
np.testing.assert_array_equal(l1b_de["spin_bin"], expected_pointing_lons)


def test_badtimes_no_spin():
Expand Down